³₅ of Archie's savings comprised of 20-cent coins and 10-cent coins. Archie used some 20-cent coins to purchase a mini plane. The number of 10-cent coins left was 50% more than the number of 20-cent coins left. Given that Archie had 24 more 10-cent coins than 20-cent coins left in the end, find the amount of money Archie spent on the mini plane.

	20-cent coins	10-cent coins
Before	3x3 = 9 u	2x3 = 6 u
Change	- 5 u
After	2x2 = 4 u	3x2 = 6 u

Fraction of Archie's savings that comprised of 10-cent coins
= 1 - ³₅
= ²₅

Number of 10-cents coins in the end in percentage
= 100% + 50%
= 150%

150% = ¹⁵⁰₁₀₀ = ³₂

Number of 10-cent coins remains unchanged. Make the number of 10-cent coins the same.  LCM of 2 and 3 is 6.

Number of more 10-cent coins than 20-cent coins
= 6 u - 4 u
= 2 u

2 u = 24

1 u = 24 ÷ 2 = 12

Number of 20-cent coins spent on the mini plane 
= 9 u - 4 u
= 5 u
= 5 x 12
= 60

Amount that Archie spent on the mini plane 
= 60 x 0.2
= $12

Answer(s): $12