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

Number of Pennies = 30

Number of Dimes = 90

Step-by-step 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