Winnie had $420 less than Pierre. Pierre spent 0.6 of his money and Winnie spent 0.3 of her money. In the end, Pierre and Winnie had the same amount of money left. Find the amount of money Winnie had at first.

	Winnie	Pierre	Difference
Before	20 u	35 u	15 u
Change	- 2 u	- 7 u
After	14 u	14 u

0.6 = ³₅

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

0.3 = ³₁₀

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

The amount that Pierre and Winnie each had in the end is the same. Make the numerators the same. LCM of 2 and 7 is 14.

²₅ of Pierre's amount = ⁷₁₀ of Winnie's amount
¹⁴₃₅ of Pierre's amount = ¹⁴₂₀ of Winnie's amount

Amount that Winnie had less than Pierre
= 35 u - 20 u
= 15 u

15 u = 420

1 u = 420 ÷ 15 = 28

Amount that Winnie had at first
= 20 u
= 20 x 28
= $560

Answer(s): $560