Question

Harrison has $9.30 in his coin collection all in pennies and dimes the number of dimes is three times the number of pennies how many coins of each type does she have

Answer 1

Number of Pennies = 30

Number of Dimes = 90

Explanation:

Let the number of pennies be p and number of dimes be d

We can write 2 equations and use substitution method to solve.

Total value of all the coins is 9.30:

We can write:

0.01p + 0.1d = 9.30

Note: value of penny is 0.01 and dime is 0.1, in dollars

Number of dimes is 3 times number of pennies:

We can write:

d = 3p

Now putting 2nd equation in first and solving for p:

0.01p + 0.1(3p) = 9.30

0.01p + 0.3p = 9.30

0.31 p = 9.30

p = 9.30 /0.31

p = 30

Now we know d = 3p, so d = 3 (30) = 90

Hence

Number of Pennies = 30

Number of Dimes = 90