58 of Jack's savings comprised of 10-cent coins and 50-cent coins. Jack used some 10-cent coins to purchase a yoyo. The number of 50-cent coins left was 40% more than the number of 10-cent coins left. Given that Jack had 114 more 50-cent coins than 10-cent coins left in the end, find the amount of money Jack spent on the yoyo.
|
10-cent coins |
50-cent coins |
Before |
5x7 = 35 u |
3x7 = 21 u |
Change |
- 20 u |
|
After |
5x3 = 15 u |
7x3 = 21 u |
Fraction of Jack's savings that comprised of 50-cent coins
= 1 -
58=
38Number 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 3 and 7 is 21.
Number of more 50-cent coins than 10-cent coins
= 21 u - 15 u
= 6 u
6 u = 114
1 u = 114 ÷ 6 = 19
Number of 10-cent coins spent on the yoyo
= 35 u - 15 u
= 20 u
= 20 x 19
= 380
Amount that Jack spent on the yoyo
= 380 x 0.1
= $38
Answer(s): $38