Work Efficiency MCQ Quiz - Objective Question with Answer for Work Efficiency - Download Free PDF
Last updated on Jul 7, 2025
Latest Work Efficiency MCQ Objective Questions
Work Efficiency Question 1:
The efficiency ratio of A, B, and C is 12:16:15 respectively. C alone complete work in 72 days. A, B and C together start work, after 6 days C left the work and A and B together work for 12 days then B left the work. Remaining work complete by A in x day then find the value of x2?
Answer (Detailed Solution Below)
Work Efficiency Question 1 Detailed Solution
Calculation
Efficiency ratio A : B : C = 12 : 16 : 15
C completes work alone in 72 days.
Total work = 15 x 72 = 1080 units
A, B, C work together for 6 days → 43 units/day x 6 = 258 units
A and B work for 12 days → 28 units/day x 12 = 336 units
Work done = 258 + 336 = 594 units
Remaining = 1080 - 594 = 486 units
A's efficiency = 12
→ Time = 486/12 = 40.5 days
Answer: x² = (40.5)² = 1640.25
Work Efficiency Question 2:
Varun and Ashish together can paint a hall in 3 days. Varun alone can paint it in 7 days. In how many days can Ashish alone paint 4 such halls?
Answer (Detailed Solution Below)
Work Efficiency Question 2 Detailed Solution
Given:
Varun and Ashish together paint 1 hall in 3 days
Varun alone paints 1 hall in 7 days
Formula used:
Work = Efficiency × Time
Calculation:
LCM of 3 and 7 = 21 units (total work)
Varun's 1 day work = 21 ÷ 7 = 3 units
Together 1 day work = 21 ÷ 3 = 7 units
⇒ Ashish's 1 day work = 7 - 3 = 4 units
1 hall = 21 units
4 halls = 4 × 21 = 84 units
Time = 84 ÷ 4 = 21 days
∴ Ashish alone can paint 4 halls in 21 days.
Work Efficiency Question 3:
The ratio of the efficiency of worker A to worker B is 5:3. When B works with a third worker, C, they complete a job in 12 days. When A and C work together, they complete the same job in 9 days. If C takes Y days to complete the job alone, what is the value of Y/3?
Answer (Detailed Solution Below)
Work Efficiency Question 3 Detailed Solution
Given:
Efficiency ratio A : B = 5 : 3
B + C complete work in 12 days
A + C complete work in 9 days
C alone completes in Y days
Formula used:
Work = LCM of days taken
Efficiency = Work ÷ Time
Efficiency A : B = 5 : 3
Calculations:
Let total work = 180 units (LCM of 12 and 9)
B + C = 180 ÷ 12 = 15 units/day
A + C = 180 ÷ 9 = 20 units/day
Let efficiency of A = 5x ⇒ B = 3x
A + C = 20 ⇒ 5x + C = 20 ⇒ C = 20 - 5x
B + C = 15 ⇒ 3x + C = 15 ⇒ C = 15 - 3x
Equating both:
20 - 5x = 15 - 3x
⇒ 5 = 2x ⇒ x = 2.5
⇒ C = 20 - 5x = 20 - 12.5 = 7.5 units/day
Y = 180 ÷ 7.5 = 24
⇒ Y/3 = 24 ÷ 3 = 8
∴ Y/3 = 8
Work Efficiency Question 4:
A and B alone can do a piece of work in 4 and 9 days, respectively. In how many days will the work be completed, if they both work on alternate days, starting with B?
Answer (Detailed Solution Below)
Work Efficiency Question 4 Detailed Solution
Given:
A can do a piece of work = 4 days
B can do a piece of work = 9 days
Formula used:
Total work = efficiency × time
Calculation:
| Efficiency | Person | Time | Total work |
| 9 | A | 4 | 36 |
| 4 | B | 9 |
Now,
(B + A) = 4 + 9 = 13 units = 2 days
⇒ (13 × 2) = 26 units = (2 × 2) = 4 days
⇒ 30 units = 5 days
⇒ 36 units = 5 + (6/9) = 5
∴ The correct answer is 5
Work Efficiency Question 5:
A and B together can complete a piece of work in 15 days and B alone is 20 days. In how many days can A alone complete the work?
Answer (Detailed Solution Below)
Work Efficiency Question 5 Detailed Solution
Given:
A and B together can complete a piece of work in 15 days.
B alone can complete the work in 20 days.
Concept used:
The work rate is the amount of work done per day by an individual or a group.
Calculation:
Let RA be the work rate of A (in units of work per day), and RB be the work rate of B.
A and B together can complete the work in 15 days, so their combined work rate is
RA + RB =
B alone can complete the work in 20 days, so B's work rate is
RB =
Now, substitute Equation 2 into Equation 1:
RA +
RA =
RA =
So, the work rate of A is
Now, to find out how many days A alone would take to complete the work, use the formula:
Time (in days) =
In this case, the total work is 1 (since they are completing one piece of work), and A's work rate is
Time (A alone) =
∴ A alone can complete the work in 60 days.
Top Work Efficiency MCQ Objective Questions
A and B together can do a piece of work in 50 days. If A is 40% less efficient than B, in how many days can A working alone complete 60% of the work?
Answer (Detailed Solution Below)
Work Efficiency Question 6 Detailed Solution
Download Solution PDFGiven:
A and B together can do a piece of work in 50 days.
A is 40% less efficient than B
Concept used:
Total work = Efficiency of the workers × time taken by them
Calculation:
Let the efficiency of B be 5a
So, efficiency of A = 5a × 60%
⇒ 3a
So, total efficiency of them = 8a
Total work = 8a × 50
⇒ 400a
Now,
60% of the work = 400a × 60%
⇒ 240a
Now,
Required time = 240a/3a
⇒ 80 days
∴ A can complete 60% of the work working alone in 80 days.
Shortcut Trick
We know 40% = 2/5, Efficiency of B = 5 and A = 3
So, Total work = (5 + 3) × 50 = 400 units
So, 60% of the total work = 60% of 400 = 240 units
So A alone can do the work in 240/3 = 80 days
A can finish a work in 15 days, B can finish the same work in 25 days. They work together for 5 days. The rest of the work is finished by A and C in 4 days. Then C alone can finish the work in:
Answer (Detailed Solution Below)
Work Efficiency Question 7 Detailed Solution
Download Solution PDFGiven:
A can finish in 15 days, B can finish it in 25 days.
They work together for 5 days.
Concept used:
Efficiency = (Total work / Total time taken)
Efficiency = work done in a single day
Calculation:
Let total work be 75 units ( LCM of 15 and 25 is 75)
The efficiency of A
⇒ 75 /15 = 5 units
The efficiency of B
⇒ 75 / 25 = 3 units
The efficiency of A+B,
⇒ (5 + 3) units = 8 units
In 5 days total work done is 8 × 5 = 40 units
Remaining work 75 - 40 = 35 units
In the last 4 days, A does 4 × 5 = 20 units
Remaining work 35 - 20 = 15 units done by C in 4 days
So C does 75 units in (75 / 15) × 4 = 20 days
∴ The correct option is 3
23 people could do a piece of work in 18 days. After 6 days 8 of the workers left. How many days from then will it take to complete the work?
Answer (Detailed Solution Below)
Work Efficiency Question 8 Detailed Solution
Download Solution PDFGiven:
23 people could do a piece of work in 18 days.
After 6 days 8 of the workers left.
Concept used:
Total work = Men needed × Days needed to finish it entirely
Calculation:
Total work = 23 × 18 = 414 units
In 6 days, total work done = 23 × 6 = 138 units
Remaining work = (414 - 138) = 276 units
Time taken to complete the remaining work = 276 ÷ (23 - 8) = 18.4 days
∴ 18.4 days it will take to finish the work.
The efficiency of A, B, and C is 2 : 3 : 5. A alone can complete a work in 50 days. They all work together for 5 days and then C left the work, in how many days A and B together can complete the remaining work?
Answer (Detailed Solution Below)
Work Efficiency Question 9 Detailed Solution
Download Solution PDFGiven:
Efficiency of A, B and C = 2 : 3 : 5
A alone can complete the work in = 50 days
Formula:
Total work = Efficiency × Time
Calculation:
Let efficiency of A be 2 units/day
Efficiency of A, B and C = 2 : 3 : 5
Total work = 2 × 50 = 100 units
Work done by A, B and C in 5 days = (2 + 3 + 5) × 5 = 10 × 5 = 50 units
Remaining work = 100 – 50 = 50 units
∴ Time taken by A and B to complete the remaining work = 50/(2 + 3) = 50/5 = 10 days
A,B and C can do a piece of work in 30 days, 40 days and 50 days, respectively. Beginning with A, if A, B and C do the work alternatively then in how many days will the work be finished?
Answer (Detailed Solution Below)
Work Efficiency Question 10 Detailed Solution
Download Solution PDFGiven:
A can do a piece of work = 30 days
B can do a piece of work = 40 days
C can do a piece of work = 50 days
Formula used:
Total work = efficiency × time
Calculation:
| Efficiency | Person | Time | Total work |
| 20 | A | 30 | 600 |
| 15 | B | 40 | |
| 12 | C | 50 |
According to the question:
⇒ (20 + 15 + 12) = 47 units = 3 days
⇒ 47 × 12 = 564 units = 3 × 12 = 36 days
⇒ (564 + 20 + 15) = 599 units = 38 days
Total work = 600 units = 38 + (1/12) = 38
∴ The correct answer is 38
If 'A' is 6 times more efficient than 'B', 'B' takes 32 days to complete the task, then find the number of days required to finish the whole work by 'A' and 'B' working together.
Answer (Detailed Solution Below)
Work Efficiency Question 11 Detailed Solution
Download Solution PDFGiven:
A is 6 times more efficient than B, & B takes 32 days to complete the task.
Formula used:
Total work = Efficiency × Time taken
Calculation:
A is 6 times more efficient than B
Efficiency of A ∶ Efficiency of B = 7 ∶ 1
Total work = Efficiency of B × Time taken
⇒ 1 × 32 = 32 units
Number of days required to finish the whole work by (A + B) = Total work/Efficiency of (A+ B)
⇒ 32/8
⇒ 4
∴ The total number of days required to finish the whole work by (A + B) is 4 days.
There is a difference in "Efficient" and " More efficient"
A is 6 times efficient than B means if B is 1 then, A will be 6
A is 6 times more efficient than B means if B is 1 then, A will be (1 + 6) = 7
In the question, it is given that A is 6 times more efficient which means if B is 1, then A will (1 + 6) times = 7 times efficient
So, Total efficiency of A and B = (1 + 7) = 8 units/day
Time taken to complete the work together = 32/8 days
⇒ 4 days and this is the answer.
A and B can complete a task in 12 days. However, A had to leave a few days before the task was completed and hence it took 16 days in all to complete the task. If A alone could complete the work in 21 days, how many days before the work getting over did A leave?
Answer (Detailed Solution Below)
Work Efficiency Question 12 Detailed Solution
Download Solution PDFGiven A alone can complete the work in 21 days
A and B together can complete the same work in 12 days
⇒ Total work = L.C.M of (12, 21) = 84
⇒ One day work of A = 4
⇒ One day work of (A + B) = 7
⇒ One day work of B = 3
Let A worked for x days and B worked for 16 days
⇒ 4x + 3 × 16 = 84
⇒ x = 9 days
∴ A left the work before (16 - 9 =) 7 days.
To do a certain work, A and B work on alternate days with B beginning the work on the first day. A alone can complete the same work in 24 days. If the work gets completed in
Answer (Detailed Solution Below)
Work Efficiency Question 13 Detailed Solution
Download Solution PDFGiven:
A can complete the work in 24 days
A and B work on alternate days with B beginning the work, can complete the work in
Formula Used:
Total Work = Efficiency × Time
Calculation:
Let the total work be 24 units
⇒ Efficiency of A = 24/24 = 1 unit
According to the question,
A works on 2nd, 4th, 6th, 8th, 10th and (1/3) of 12th day
⇒ A works for 5(1/3) = 16/3 days
⇒ B works for =
⇒ Work done by A in 16/3 days = 16/3 units
Remaining work = 24 - (16/3) = 56/3 units
⇒ 56/3 units are completed by B in 6 days
(7/9)th part of 24 = (24 × 7)/9 = 56/3 units
∴ B alone will complete (7/9)th of the original work in 6 days.
Alternate Method
Given:
Time taken by A to finish a task alone = 24 days
Calculation:
Let the total work be = 1
A alone can finish the task in 24 days
⇒ A's one-day work = 1/24
A and B complete the whole task in =
A and B work on alternate days, with B beginning so, we can say B will work only 6 days
⇒ A will work only
If A's one day work = 1/24 of work A completes in 1 day
⇒ A's
⇒ 2/9
Remaining work = 1 - 2/9 = 7/9
∴ B does the 7/9th part of the work in 6 days.
Note-
B, A, B, A, B, A, B, A, B, A, B, A/3
B completely 6-day work
That's why we have taken the 6 days work by B alone.
A and B together can complete a certain work in 20 days whereas B and C together can complete it in 24 days. If A is twice as good a workman as C, then in what time will B alone do 40% of the same work?
Answer (Detailed Solution Below)
Work Efficiency Question 14 Detailed Solution
Download Solution PDFGiven:
A = 2C
A + B in 20 days
B + C in 24 days
Concept used:
Total work = LCM of time taken by the workers
Calculation:
LCM of 20 and 24 is 120
So, efficiency of A and B = 120/20 = 6 and efficiency of B and C = 120/24 = 5
Now 2C + B = 6 and B + C = 5
So, C = 1
B = 4
40% of the work = 120 × 2/5 = 48 units
So, B will take 48/4 = 12 days
∴ B alone do 40% of the same work in 12 days
Shortcut Trick
Now 2C + B = 6 and B + C = 5
So, C = 1
B = 4
So,
A, B and C = 2, 4, and 1
40% of the work = 120 × 2/5 = 48 units
So, B will take 48/4 = 12 days
To do a certain work, Ajay and Bharat work on alternate days, with Bharat starting the work on the first day. Ajay can finish the work alone in 32 days. If the work gets completed in exactly 8 days, then Bharat alone can finish 7 times the same work in ____________ days.
Answer (Detailed Solution Below)
Work Efficiency Question 15 Detailed Solution
Download Solution PDFFormula Used:
Total work = Efficiency × Time taken
Calculation
Ajay can finish the work alone in 32 days
A’s one day work = 1/32
A and B complete the whole work in = 8 days
Ajay and Bharat work on alternate days, with Bharat starting the work on the first day so, we can say B will work only 4 days A will work only:
= 8 - 4 = 4 days
If A’s 4-day work = 4/32 = 1/8
Remaining work = 1 – [1/8] = 7/8
B complete 7/8 work in = 4 days
B complete whole work in = 4 × [8/7] = 32/7 days
B alone can finish 7 times the same work in = [32/7] × 7 = 32 days
B alone can finish 7 times the same work in 32 days.