Changing ratio word problem

Let  A  be the equal amount spent  by each....and we know that

[ 160  - A ]          3

_________  =   ___             cross-multiply

[ 240 - A ]           5

5 [ 160  - A ]   =  3 [ 240 - A]     simplify

800 - 5A =  720 - 3A      add 5A to both sides, subract 720 from each side

80  =  2A     divide  both side  by 2

$40  = A  = amt each spent

Bob had 160 and Jay had 240 at first. Each boy spent an equal amount of money. Then the ratio of the amount of money bob had left to the amount of money Jay had left was 3:5. How much money did each boy spend?

(160 - x) / (240 - x) = 3 / 5

x = 40