Problema Solution

A piggy bank contains 39 coins, all in nickels and dimes. The coins have a value of $3.40. How many of each type of coin does the bank contain?

Answer provided by our tutors

1 nickel = 5 cents

1 dime = 10 cents

Let

n = the number of nickels, n>=0, n is integer

d = the number of dimes, d>=0, d is integer

A piggy bank contains 39 coins consisting of nickels and dimes:

n + d = 39

The total value of the coins is $3.40 = 340 cents:

5n + 10d = 340 divide both sides by 5

n + 2d = 68

by solving the system of equations:

n + d = 39

n + 2d = 68

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n = 10 nickels

d = 29 dimes

The piggy bank contains 10 nickels and 29 dimes.