Question

A and B both have some pencils. if A gives 10 pencils to B , then B will have twice as  many as A. and if B gives 10 pencils to A, then they will have the same number of pencils. how many pencils does each has?

Answer 1

If A has A pencils and B has B pencils:

After giving 10 pencils to B, A has A-10 pencils and B has B+10 pencils, so B+10=2(A-10).

After giving 10 pencils to A, B has B pencils again and A has A pencils again, so A=B.

B+10=2(A-10) is therefore the same as A+10=2A-20, A=30. So B=A=30.

They each have 30 pencils.