Question

I need help? I don't know what I did wrong in this question?

Answer 1

Find the amount of dimes and amount of quarters.

What you know:

Types of coins: dimes and quarters
Total # of coins: 35 coins
Dollar amount: $6.50

- d = dimes
- q = quarters

Work:

d + q = 35
$0.10d + $0.25q = $6.50
Let’s solve the first equation for q.
Subtract d from both sides.
- q = -d + 35

Substitute expression for q in second equation.
0.10d + 0.25(-d + 35) = 6.50
Distribute.
0.10d – 0.25d + 8.75 = 6.50
Add like terms.
0.35d + 8.75 = 6.50
Subtract 8.75 from both sides.
0.35d = -2.25

I don't understand what to do next?

Answer 2

third last line, you combined 0.1d and -0.25d and got 0.35d.
it should be -0.15d

Answer 3

@Mathmuse ohh ohk thank you I didn't see that