Question

Kat has 19 coins, all quarters and dimes, that are worth a total of $4. The system of equations that can be used to find the number of quarters, q, and the number of dimes, d, she has is shown.

q + d=19
0.25q + 0.1d=4

How many quarters does she have?

4
5
14
15

Answer 1

since we are trying to figure out the number of quarters we need to cancel out the $ (d)
-0.1(q + d=19)
0.25q + 0.1d=4

Opposites cancel
-0.1q -0.1 d=1.9
0.25q + 0.1d=4

Answer 2

Can you finish from here?

Answer 3

no i cant