Barbara had $320 less than Bobby. Bobby spent 0.6 of his money and Barbara spent 0.4 of her money. In the end, Bobby and Barbara had the same amount of money left. Find the amount of money Barbara had at first.

	Barbara	Bobby	Difference
Before	10 u	15 u	5 u
Change	- 2 u	- 3 u
After	6 u	6 u

0.6 = ³₅

Fraction of Bobby's amount left
= 1 - ³₅
= ²₅

0.4 = ²₅

Fraction of Barbara's amount left
= 1 - ²₅
= ³₅

The amount that Bobby and Barbara each had in the end is the same. Make the numerators the same. LCM of 2 and 3 is 6.

²₅ of Bobby's amount = ³₅ of Barbara's amount
⁶₁₅ of Bobby's amount = ⁶₁₀ of Barbara's amount

Amount that Barbara had less than Bobby
= 15 u - 10 u
= 5 u

5 u = 320

1 u = 320 ÷ 5 = 64

Amount that Barbara had at first
= 10 u
= 10 x 64
= $640

Answer(s): $640