Question

A video store is selling old DVDs and video games. They charge $3 for each video game and $4 for each DVD. You buy a combination of 15 DVDs and games, and spend $51. How many of each did you buy?
A. 9 games and 6 DVDs
B. 10 games and 5 DVDs
C. 11 games and 4 DVDs
D. 12 games and 3 DVDs

Answer 1

let

v = # of video games bought
d = # of dvds bought

since you bought 15 items total, you know

v+d = 15

Answer 2

because "They charge $3 for each video game and $4 for each DVD" and you spent $51, you know that

3v + 4d = 51

Answer 3

So you can solve the first equation for v to get

v+d = 15

v = 15-d

then plug this into the second equation to get

3v + 4d = 51

3(15 - d) + 4d = 51

45 - 3d + 4d = 51

d + 45 = 51

I'll let you finish up

Answer 4

thank you ! @jim_thompson5910

Answer 5

you're welcome