A bag contained some 20-cent and 50-cent coins. There were 14 fewer 50-cent coins than 20-cent coins. The total amount of money in the bag was $27.30. How many 50-cents were there.

Answer:35.50

Step-by-step explanation:

On edg

The bag contains "some" 20-cent and "some" 50-cent coins. I assume that some means more than 1, so I start assuming the bag had 2 50-cent coins. Since there were 14 fewer 50-cent coins than 20-cent coins, for any guess of the number of 50-cent coins, you must use 14 more 20-cent coins.

1st guess: 2 50-cent coins + 16 20-cent coins

Value: 2 * $0.5 + 16 * $0.2 = $4.20

Since the difference in the numbers of coins is always 14, each time we add one 50-cent coin and 1 20-cent coin, the value goes up by $0.70.

$27.30 - $4.20 = $23.10

Our first guess is low in value by $23.10. How many additions of $0.70 (one coin of each) will it take to get the full value of $27.30?

$23.10/$0.70 = 33

By adding 33 pairs of coins to the 2 50-cent coins and 16 20-cent coins, the value will be $27.30.

Number of 50-cent coins = 2 + 33 = 35

Check: If there are 35 50-cent coins, there are 35 + 14 = 49 20-cent coins.

Value: 35 * $0.5 + 49 * $0.2 = $17.50 + $9.80 = $27.30

35 50-cent coins plus 49 20-cent coins do add up to a value of $27.30, so answer of 35 50-cent coins is correct.