Certain number of birds are sitting on two trees A and B. If a bird from the tree B goes to the tree A, then no. of birds on the two trees become equal. However, if a bird from tree A goes to tree B, then the no. of birds on the tree B becomes twice that of A. How many birds are there on the trees A and B, respectively?

Correct option is C

Solution:
Directly checking the options
If a bird from tree B comes to A then number of birds become equal
In option(a) 3,5
If one bird comes from B to A then birds become 4,4
Hence this condition is satisfied
Secondly if a bird goes from A to B then number of birds on tree B becomes twice of that of tree A
Here if a bird goes from A to b then count becomes 2,6 but 6 is thrice of 2 so the condition is not satisfied
In second option(b) 7,6
If a bird goes from B to A then count becomes 8,5
So condition is not satisfied
In option(c) 5,7
If a bird goes from B to A count becomes 6,6 hence condition is satisfied
And if one bird goes from A to B then count becomes 4,8 hence 8 is twice of 4 so condition is satisfied
So the correct answer is 5,7 , option(c)