A coin box contained some twenty-cent and fifty-cent coins in the ratio

4:3. After 20 twenty-cent coins were taken out to exchange for fifty-cents coins of the same value and put back in the box, the ratio of the number of twenty-cent coins to the number of fifty-cents coins became 7:11. Find the sum of money in the box.

1 answer

If there are 4x 20¢ coins, there are 3x 50¢ coins.

20 20¢ coins = $4.00, or 8 50¢ coins.

So, we have

(4x-20)/(3x+8) = 7/11
x = 12

So, now you can figure the value of the money.