Total number of initial calls in the company is 24000 and total number of calls not received by company C is 4464 less than the total number of calls received by company A. Find the value of y.

Calculation: 

Let the total number of calls be 1000z.

Initial calls (% out of total calls) of A = (1000z × 40/100) = 400z

Initial calls (% out of total calls) of B = (1000z × 30/100) = 300z

Initial calls (% out of total calls) of C = (1000z × 30/100) = 300z

Lead calls (% out of initial calls) of A = (400z × 80/100) = 320z

Lead calls (% out of initial calls) of B = (300z × x/100) = 3zx

Lead calls (% out of initial calls) of C = (300z × 88/100) = 264z

Final received calls (% out of lead calls) of A = (320z × 90/100) = 288z

Final received calls (% out of lead calls) of B = (3zx × 80/100) = 3zx × (4/5)

Final received calls (% out of lead calls) of C = (264z × y/100)

Total number of initial calls in the company = 24000

⇒ (400z + 300z + 300z) = 24000

⇒ 1000z = 24000

⇒ z = (24000/1000)

⇒ z = 24

Total number of calls not received calls by C = (300h – 264z × y/100)

⇒ (300 × 24 –  264z × y/100)

⇒ (7200 – 264z × y/100)

According to the question

Total number of calls not received by company C is 4464 less than the total number of calls received by company A

⇒ (7200 – 264z × y/100) + 4464 = 288z

⇒ (7200 – 264 × 24 × y/100) + 4464 = 288 × 24

⇒ 7200 – 6336y/100 + 4464 = 6912

⇒ (720000 – 6336y + 446400)/100 = 6912

⇒ (720000 – 6336y + 446400) = 6912 × 100

⇒ (1166400 – 6336y) = 691200

⇒ (-6336y) = (691200 – 1166400)

⇒ (-6336y) = -475200

⇒ y = [-475200/(-6336)]

⇒ y = 75

∴ The value of y is 75