The number of five-cent coins in a jar was
15 the number of ten-cent coins. Justin took out 23 ten-cent coins and exchanged them for five-cent coins. Then he put the money back into the jar. The number of ten-cent coins became
25 the number of five-cent coins. How much money was there in the jar?
|
Make u the same (1)x5 = (3) |
5-cent (1) |
10-cent (2) |
Before |
5 u |
1 u |
5 u |
Change |
+ 230 |
+ 46 |
- 23 |
After |
25 p |
5 p |
2 p |
Value of 10-cent coins to be exchanged to 5-cent coins
= 23 x 10
= 230
Number of 5-cent coins to be exchanged from the 10-cent coins
= 230 ÷ 5
= 46
(3) = (2)
25 p - 230 = 2 p + 23
25 p - 2 p = 23 + 230
23 p = 253
1 p = 253 ÷ 23 = 11
Number of 5-cent coins in the end
= 5 p
= 5 p x 11
= 55
Value of 5-cent coins in the end
= 55 x 5
= 275¢
Number of 10-cent coins in the end
= 2 p
= 2 x 11
= 22
Value of 10-cent coins in the end
= 22 x 10
= 220¢
Total value of coins
= 275 + 220
= 495¢
$1 = 100¢
495¢ = $4.95
Answer(s): $4.95