⁵₉ of Ahmad's savings comprised of 5-cent coins and 10-cent coins. Ahmad used some 5-cent coins to purchase a flying saucer. The number of 10-cent coins left was 50% more than the number of 5-cent coins left. Given that Ahmad had 80 more 10-cent coins than 5-cent coins left in the end, find the amount of money Ahmad spent on the flying saucer.

	5-cent coins	10-cent coins
Before	5x3 = 15 u	4x3 = 12 u
Change	- 7 u
After	2x4 = 8 u	3x4 = 12 u

Fraction of Ahmad's savings that comprised of 10-cent coins
= 1 - ⁵₉
= ⁴₉

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 4 and 3 is 12.

Number of more 10-cent coins than 5-cent coins
= 12 u - 8 u
= 4 u

4 u = 80

1 u = 80 ÷ 4 = 20

Number of 5-cent coins spent on the flying saucer 
= 15 u - 8 u
= 7 u
= 7 x 20
= 140

Amount that Ahmad spent on the flying saucer 
= 140 x 0.05
= $7

Answer(s): $7