Xandra had $325 less than David. David spent 0.8 of his money and Xandra spent 0.3 of her money. In the end, David and Xandra had the same amount of money left. Find the amount of money Xandra had at first.

	Xandra	David	Difference
Before	10 u	35 u	25 u
Change	- 1 u	- 7 u
After	7 u	7 u

0.8 = ⁴₅

Fraction of David's amount left
= 1 - ⁴₅
= ¹₅

0.3 = ³₁₀

Fraction of Xandra's amount left
= 1 - ³₁₀
= ⁷₁₀

The amount that David and Xandra each had in the end is the same. Make the numerators the same. LCM of 1 and 7 is 7.

¹₅ of David's amount = ⁷₁₀ of Xandra's amount
⁷₃₅ of David's amount = ⁷₁₀ of Xandra's amount

Amount that Xandra had less than David
= 35 u - 10 u
= 25 u

25 u = 325

1 u = 325 ÷ 25 = 13

Amount that Xandra had at first
= 10 u
= 10 x 13
= $130

Answer(s): $130