Need a bit of help please

Question

You have 2 stacks of notebooks on a desk. There are 2.5 times more notebooks in one stack than in the other. You moved 5 notebooks from the second pile to the first. Now the second stack has 3 times less notebooks than the first. How many notebooks did you have in each pile at the beginning?

Answer 1

A = number in 1st stack

B = number in 2nd stack

 

A = 2.5B

 

A = 3(B-5)

 

3(B-5) = 2.5B

3B - 15 = 2.5B

0.5B - 15 = 0

0.5B = 15

B = 30

 

A = 2.5B = 75

 

1st stack had 75, 2nd stack had 30