Hi
Let x represent the number in the original group
Question states***
160/x - 160/(x+1) = $8
Solving for x
160(x+1) - 160x = 8x(x+1)
8x^2 + 8x -160 = 0
x^2 + x - 20 = 0
(x+5)(x-4)=0 x = 4 |tossing out negative solution for count
CHECKING our Answer***
160/4 - 160/5 = $40 - $32 = $8