The number of five-cent coins in a pouch was
14 the number of twenty-cent coins. Lee took out 25 twenty-cent coins and exchanged them for five-cent coins. Then he put the money back into the pouch. The number of twenty-cent coins became
35 the number of five-cent coins. How much money was there in the pouch?
|
Make u the same (1)x4 = (3) |
5-cent (1) |
20-cent (2) |
Before |
4 u |
1 u |
4 u |
Change |
+ 400 |
+ 100 |
- 25 |
After |
20 p |
5 p |
3 p |
Value of 20-cent coins to be exchanged to 5-cent coins
= 25 x 20
= 500
Number of 5-cent coins to be exchanged from the 20-cent coins
= 500 ÷ 5
= 100
(3) = (2)
20 p - 400 = 3 p + 25
20 p - 3 p = 25 + 400
17 p = 425
1 p = 425 ÷ 17 = 25
Number of 5-cent coins in the end
= 5 p
= 5 p x 25
= 125
Value of 5-cent coins in the end
= 125 x 5
= 625¢
Number of 20-cent coins in the end
= 3 p
= 3 x 25
= 75
Value of 20-cent coins in the end
= 75 x 20
= 1500¢
Total value of coins
= 625 + 1500
= 2125¢
$1 = 100¢
2125¢ = $21.25
Answer(s): $21.25