5. A box contained 50cent coins and 20cent coins in the ratio 2:3. When I took out four 50cent coins, exchanged them for 20cent coins, and then put the money back into the box, the ratio became 2:7. Find the sum of money in the box.
4 x 50 = 200
200 ÷ 20 = 10
50¢ 20¢ 3 x 50¢ 2 x 20¢
---------------------------------------
2 : 3 6 : 6
- 4 + 10 - 12 + 20
---------------------------------------
2 : 7 6 : 14
---------------------------------------
6 u + 12 --> 14 u – 20
8 u --> 12 + 20 = 32
1 u --> 32 ÷ 8 = 4
2 x 4 = 8
8 x 0.50 = $4
7 x 4 = 28
28 x 0.20 = $5.60
4 + 5.60 = $9.60
The sum of money in the box was $9.60.
No comments:
Post a Comment