The number of ten-cent coins in a jar was
14 the number of fifty-cent coins. Ryan took out 18 fifty-cent coins and exchanged them for ten-cent coins. Then he put the money back into the jar. The number of fifty-cent coins became
25 the number of ten-cent coins. How much money was there in the jar?
|
Make u the same (1)x4 = (3) |
10-cent (1) |
50-cent (2) |
Before |
4 u |
1 u |
4 u |
Change |
+ 360 |
+ 90 |
- 18 |
After |
20 p |
5 p |
2 p |
Value of 50-cent coins to be exchanged to 10-cent coins
= 18 x 50
= 900
Number of 10-cent coins to be exchanged from the 50-cent coins
= 900 ÷ 10
= 90
(3) = (2)
20 p - 360 = 2 p + 18
20 p - 2 p = 18 + 360
18 p = 378
1 p = 378 ÷ 18 = 21
Number of 10-cent coins in the end
= 5 p
= 5 p x 21
= 105
Value of 10-cent coins in the end
= 105 x 10
= 1050¢
Number of 50-cent coins in the end
= 2 p
= 2 x 21
= 42
Value of 50-cent coins in the end
= 42 x 50
= 2100¢
Total value of coins
= 1050 + 2100
= 3150¢
$1 = 100¢
3150¢ = $31.50
Answer(s): $31.50