Marion had $500 less than Ahmad. Ahmad spent 0.6 of his money and Marion spent 0.4 of her money. In the end, Ahmad and Marion had the same amount of money left. Find the amount of money Marion had at first.

	Marion	Ahmad	Difference
Before	10 u	15 u	5 u
Change	- 2 u	- 3 u
After	6 u	6 u

0.6 = ³₅

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

0.4 = ²₅

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

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

²₅ of Ahmad's amount = ³₅ of Marion's amount
⁶₁₅ of Ahmad's amount = ⁶₁₀ of Marion's amount

Amount that Marion had less than Ahmad
= 15 u - 10 u
= 5 u

5 u = 500

1 u = 500 ÷ 5 = 100

Amount that Marion had at first
= 10 u
= 10 x 100
= $1000

Answer(s): $1000