The number of five-cent coins in a jar was
15 the number of ten-cent coins. Simon took out 18 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
35 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 |
+ 180 |
+ 36 |
- 18 |
After |
25 p |
5 p |
3 p |
Value of 10-cent coins to be exchanged to 5-cent coins
= 18 x 10
= 180
Number of 5-cent coins to be exchanged from the 10-cent coins
= 180 ÷ 5
= 36
(3) = (2)
25 p - 180 = 3 p + 18
25 p - 3 p = 18 + 180
22 p = 198
1 p = 198 ÷ 22 = 9
Number of 5-cent coins in the end
= 5 p
= 5 p x 9
= 45
Value of 5-cent coins in the end
= 45 x 5
= 225¢
Number of 10-cent coins in the end
= 3 p
= 3 x 9
= 27
Value of 10-cent coins in the end
= 27 x 10
= 270¢
Total value of coins
= 225 + 270
= 495¢
$1 = 100¢
495¢ = $4.95
Answer(s): $4.95