⁴₅ of Warren's savings comprised of 10-cent coins and 50-cent coins. Warren used some 10-cent coins to purchase a basketball set. The number of 50-cent coins left was 40% more than the number of 10-cent coins left. Given that Warren had 20 more 50-cent coins than 10-cent coins left in the end, find the amount of money Warren spent on the basketball set.

	10-cent coins	50-cent coins
Before	4x7 = 28 u	1x7 = 7 u
Change	- 23 u
After	5x1 = 5 u	7x1 = 7 u

Fraction of Warren's savings that comprised of 50-cent coins
= 1 - ⁴₅
= ¹₅

Number of 50-cents coins in the end in percentage
= 100% + 40%
= 140%

140% = ¹⁴⁰₁₀₀ = ⁷₅

Number of 50-cent coins remains unchanged. Make the number of 50-cent coins the same.  LCM of 1 and 7 is 7.

Number of more 50-cent coins than 10-cent coins
= 7 u - 5 u
= 2 u

2 u = 20

1 u = 20 ÷ 2 = 10

Number of 10-cent coins spent on the basketball set 
= 28 u - 5 u
= 23 u
= 23 x 10
= 230

Amount that Warren spent on the basketball set 
= 230 x 0.1
= $23

Answer(s): $23