58 of Ahmad's savings comprised of 10-cent coins and 20-cent coins. Ahmad used some 10-cent coins to purchase a toy figurine. The number of 20-cent coins left was 40% more than the number of 10-cent coins left. Given that Ahmad had 108 more 20-cent coins than 10-cent coins left in the end, find the amount of money Ahmad spent on the toy figurine.
|
10-cent coins |
20-cent coins |
Before |
5x7 = 35 u |
3x7 = 21 u |
Change |
- 20 u |
|
After |
5x3 = 15 u |
7x3 = 21 u |
Fraction of Ahmad's savings that comprised of 20-cent coins
= 1 -
58=
38Number 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 3 and 7 is 21.
Number of more 20-cent coins than 10-cent coins
= 21 u - 15 u
= 6 u
6 u = 108
1 u = 108 ÷ 6 = 18
Number of 10-cent coins spent on the toy figurine
= 35 u - 15 u
= 20 u
= 20 x 18
= 360
Amount that Ahmad spent on the toy figurine
= 360 x 0.1
= $36
Answer(s): $36