59 of Archie's savings comprised of 10-cent coins and 20-cent coins. Archie used some 10-cent coins to purchase a flying saucer. The number of 20-cent coins left was 40% more than the number of 10-cent coins left. Given that Archie had 96 more 20-cent coins than 10-cent coins left in the end, find the amount of money Archie spent on the flying saucer.
|
10-cent coins |
20-cent coins |
Before |
5x7 = 35 u |
4x7 = 28 u |
Change |
- 15 u |
|
After |
5x4 = 20 u |
7x4 = 28 u |
Fraction of Archie's savings that comprised of 20-cent coins
= 1 -
59=
49Number of 20-cents coins in the end in percentage
= 100% + 40%
= 140%
140% =
140100 =
75Number of 20-cent coins remains unchanged. Make the number of 20-cent coins the same. LCM of 4 and 7 is 28.
Number of more 20-cent coins than 10-cent coins
= 28 u - 20 u
= 8 u
8 u = 96
1 u = 96 ÷ 8 = 12
Number of 10-cent coins spent on the flying saucer
= 35 u - 20 u
= 15 u
= 15 x 12
= 180
Amount that Archie spent on the flying saucer
= 180 x 0.1
= $18
Answer(s): $18