Rachel has 15 coins with a value of $2.85. if the coins are either dimes or quarters, how many coins of each does she have? write and solve using a system of equations.

We have two equations:

Number of dimes (d) + number of quarters (q) = 15 or d + q = 15

A dime is worth 10 and a quarter 25

10d + 25q = 285 (converting the money to cents)

Moving on

d = 15 - q

by substitution

10 (15 - q) + 25q = 285

150 - 10q + 25q = 285

15q = 285 - 150

15q = 135

q = 135 / 15 = 9

Therefore you have 9 quarters and 6 dimes