The number of five-cent coins in a pouch was
14 the number of ten-cent coins. Simon took out 20 ten-cent coins and exchanged them for five-cent coins. Then he put the money back into the pouch. The number of ten-cent coins became
25 the number of five-cent coins. How much money was there in the pouch?
|
Make u the same (1)x4 = (3) |
5-cent (1) |
10-cent (2) |
Before |
4 u |
1 u |
4 u |
Change |
+ 160 |
+ 40 |
- 20 |
After |
20 p |
5 p |
2 p |
Value of 10-cent coins to be exchanged to 5-cent coins
= 20 x 10
= 200
Number of 5-cent coins to be exchanged from the 10-cent coins
= 200 ÷ 5
= 40
(3) = (2)
20 p - 160 = 2 p + 20
20 p - 2 p = 20 + 160
18 p = 180
1 p = 180 ÷ 18 = 10
Number of 5-cent coins in the end
= 5 p
= 5 p x 10
= 50
Value of 5-cent coins in the end
= 50 x 5
= 250¢
Number of 10-cent coins in the end
= 2 p
= 2 x 10
= 20
Value of 10-cent coins in the end
= 20 x 10
= 200¢
Total value of coins
= 250 + 200
= 450¢
$1 = 100¢
450¢ = $4.50
Answer(s): $4.50