59 of Charlie's savings comprised of 10-cent coins and 50-cent coins. Charlie used some 10-cent coins to purchase a marble. The number of 50-cent coins left was 40% more than the number of 10-cent coins left. Given that Charlie had 160 more 50-cent coins than 10-cent coins left in the end, find the amount of money Charlie spent on the marble.
|
10-cent coins |
50-cent coins |
Before |
5x7 = 35 u |
4x7 = 28 u |
Change |
- 15 u |
|
After |
5x4 = 20 u |
7x4 = 28 u |
Fraction of Charlie's savings that comprised of 50-cent coins
= 1 -
59=
49Number of 50-cents coins in the end in percentage
= 100% + 40%
= 140%
140% =
140100 =
75Number of 50-cent coins remains unchanged. Make the number of 50-cent coins the same. LCM of 4 and 7 is 28.
Number of more 50-cent coins than 10-cent coins
= 28 u - 20 u
= 8 u
8 u = 160
1 u = 160 ÷ 8 = 20
Number of 10-cent coins spent on the marble
= 35 u - 20 u
= 15 u
= 15 x 20
= 300
Amount that Charlie spent on the marble
= 300 x 0.1
= $30
Answer(s): $30