Question

CDs and DVDs Solve by setting up a system of linear equations with 2 variables and 2 unknowns. CDs cost $5.96 more than DVDs at All Bets Are Off Electronics. How much would 6 CDs and 2 DVDs cost if 5 CDs and 2 DVDs cost $127.73?

Answer 1

6 CDs and 2 DVDs would cost $147.68.

Let c be the cost of a CD and d be the cost of a DVD.

We know that c = d+5.96.

We also know that 5c+2d = 127.73.

Substituting our value of c from the first equation into the second one, we have
5(d+5.96)+2d = 127.73

Using the distributive property,
5*d+5*5.96+2d = 127.73
5d+29.80+2d = 127.73

Combining like terms,
7d+29.80 = 127.73

Subtract 29.80 from both sides:
7d+29.80-29.80=127.73-29.80
7d = 97.93

Divide both sides by 7:
7d/7 = 97.93/7
d = 13.99
c = d + 5.96 = 13.99+5.96 = 19.95

6 CDs and 2 DVDs would be
6(19.95)+2(13.99) = 147.68