Alex dumped out his piggy bank and there were only nickels, dimes, and quarters.
There were three times as many dimes as nickels, and 40
more quarters than nickels.
If the total amount of money was $17.20, how many of each
type of coin were there?
"There are
nickels,
dimes, and
quarters.

12 nickels

36 dimes

52 quarters

Step-by-step explanation:

Let x = no. of nickels

3x = no. of dimes

x + 40 = no. of quarters

5x = value of the nickels since each nickel is 5 cents

10(3x) = 30x = value of the dimes since each dime is 10 cents

25(x + 40) = 25x + 1000 = value of the quarters since each quarter is 25 cents

Now, 5x + 30x + 25x + 1000 = 1720     ($17.20 = 1720 cents)

60x + 1000 = 1720

60x = 720

x = 12 nickels

3x = 36 dimes

x + 40 = 52 quarters

Check:  12 nickels are worth $.60

36 dimes are worth $3.60

52 quarters are worth $13

.60 + 3.60 + 13 = 17.20