The number of ten-cent coins in a bag was
14 the number of twenty-cent coins. Japheth took out 17 twenty-cent coins and exchanged them for ten-cent coins. Then he put the money back into the bag. The number of twenty-cent coins became
35 the number of ten-cent coins. How much money was there in the bag?
|
Make u the same (1)x4 = (3) |
10-cent (1) |
20-cent (2) |
Before |
4 u |
1 u |
4 u |
Change |
+ 136 |
+ 34 |
- 17 |
After |
20 p |
5 p |
3 p |
Value of 20-cent coins to be exchanged to 10-cent coins
= 17 x 20
= 340
Number of 10-cent coins to be exchanged from the 20-cent coins
= 340 ÷ 10
= 34
(3) = (2)
20 p - 136 = 3 p + 17
20 p - 3 p = 17 + 136
17 p = 153
1 p = 153 ÷ 17 = 9
Number of 10-cent coins in the end
= 5 p
= 5 p x 9
= 45
Value of 10-cent coins in the end
= 45 x 10
= 450¢
Number of 20-cent coins in the end
= 3 p
= 3 x 9
= 27
Value of 20-cent coins in the end
= 27 x 20
= 540¢
Total value of coins
= 450 + 540
= 990¢
$1 = 100¢
990¢ = $9.90
Answer(s): $9.90