35 of Luis's savings comprised of 10-cent coins and 20-cent coins. Luis used some 10-cent coins to purchase a game card. The number of 20-cent coins left was 25% more than the number of 10-cent coins left. Given that Luis had 20 more 20-cent coins than 10-cent coins left in the end, find the amount of money Luis spent on the game card.
|
10-cent coins |
20-cent coins |
Before |
3x5 = 15 u |
2x5 = 10 u |
Change |
- 7 u |
|
After |
4x2 = 8 u |
5x2 = 10 u |
Fraction of Luis's savings that comprised of 20-cent coins
= 1 -
35=
25Number of 20-cents coins in the end in percentage
= 100% + 25%
= 125%
125% =
125100 =
54Number of 20-cent coins remains unchanged. Make the number of 20-cent coins the same. LCM of 2 and 5 is 10.
Number of more 20-cent coins than 10-cent coins
= 10 u - 8 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Number of 10-cent coins spent on the game card
= 15 u - 8 u
= 7 u
= 7 x 10
= 70
Amount that Luis spent on the game card
= 70 x 0.1
= $7
Answer(s): $7