Certain number of birds are sitting on two trees A and B. Birds sitting on tree A, tell to the birds sitting on tree B, that if 2 birds from tree B shift to the tree A, then we are equal in number. However, the birds sitting on tree B, tell those sitting on A, that if two birds from your side (tree A) shift to our side (tree B), then we become double than you (tree A). How many birds are sitting on the two trees A and B, respectively?

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Question

This question was previously asked in

UGC NET Paper 1: Held on 30 Sep 2022 Shift 1

Answer 1

As per the given information,

Certain number of birds are sitting on two trees A and B.

Let,

Number of birds on tree A = a

Number of birds on tree B = b

Birds sitting on tree A, tell to the birds sitting on tree B, that if 2 birds from tree B shift to tree A, then we are equal in number.

→ (a + 2) = (b - 2)

→ a = b - 4 -----(i)

However, the birds sitting on tree B, tell those sitting on A, that if two birds from your side (tree A) shift to our side (tree B), then we become double than you (tree A).

→ (b + 2) = 2(a - 2)

→ b + 2 = 2a - 4

→ b = 2a - 4 - 2

→ b = 2a - 6 ------(ii)

Putting the value of equation (i) in (ii) we get:

→ b = 2(b - 4) - 6

→ b = 2b - 8 - 6

→ b = 2b - 14

→ b = 14

now, putting b = 14 in equation (i) we get:

→ a = 14 - 4

→ a = 10

Thus, the number of birds on tree A = 10 and the number of birds on tree B = 10.

Hence, the correct answer is "10, 14".