The number of five-cent coins in a bottle was
15 the number of ten-cent coins. Cody took out 20 ten-cent coins and exchanged them for five-cent coins. Then he put the money back into the bottle. The number of ten-cent coins became
35 the number of five-cent coins. How much money was there in the bottle?
|
Make u the same (1)x5 = (3) |
5-cent (1) |
10-cent (2) |
Before |
5 u |
1 u |
5 u |
Change |
+ 200 |
+ 40 |
- 20 |
After |
25 p |
5 p |
3 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)
25 p - 200 = 3 p + 20
25 p - 3 p = 20 + 200
22 p = 220
1 p = 220 ÷ 22 = 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
= 3 p
= 3 x 10
= 30
Value of 10-cent coins in the end
= 30 x 10
= 300¢
Total value of coins
= 250 + 300
= 550¢
$1 = 100¢
550¢ = $5.50
Answer(s): $5.50