Christine went shopping and bought each of her nine nephews a gift, either a video costing $14.95 or a CD costing $16.88. She spent $142.27 on the gifts. How many videos and how many CDs did she buy?

V + c = 9 ... v = 9 - c

14.95v + 16.88c = 142.27

14.95 (9 - c) + 16.88c = 142.27

134.55 - 14.95c + 16.88c = 142.27

-14.95c + 16.88c = 142.27 - 134.55

1.93c = 7.72

c = 7.72 / 1.93

c = 4 < = = = there were 4 CD's

v + c = 9

v + 4 = 9

v = 9 - 4

v = 5 < = = = there were 5 videos