The number of five-cent coins in a jar was
13 the number of fifty-cent coins. Will took out 21 fifty-cent coins and exchanged them for five-cent coins. Then he put the money back into the jar. The number of fifty-cent coins became
38 the number of five-cent coins. How much money was there in the jar?
|
Make u the same (1)x3 = (3) |
5-cent (1) |
50-cent (2) |
Before |
3 u |
1 u |
3 u |
Change |
+ 630 |
+ 210 |
- 21 |
After |
24 p |
8 p |
3 p |
Value of 50-cent coins to be exchanged to 5-cent coins
= 21 x 50
= 1050
Number of 5-cent coins to be exchanged from the 50-cent coins
= 1050 ÷ 5
= 210
(3) = (2)
24 p - 630 = 3 p + 21
24 p - 3 p = 21 + 630
21 p = 651
1 p = 651 ÷ 21 = 31
Number of 5-cent coins in the end
= 8 p
= 8 p x 31
= 248
Value of 5-cent coins in the end
= 248 x 5
= 1240¢
Number of 50-cent coins in the end
= 3 p
= 3 x 31
= 93
Value of 50-cent coins in the end
= 93 x 50
= 4650¢
Total value of coins
= 1240 + 4650
= 5890¢
$1 = 100¢
5890¢ = $58.90
Answer(s): $58.90