Hoe many packs of each did he buy

Question

A supply clerk for a company is ordering two kinds of light bulbs. One kind come in a pack of 24 for $12, and the other comes in a pack of 12 for $18. The clerk ordered a total of 108 light bulbs at cost of $66. How many packs of each kind did the clerk buy

Answer 1

Let

b = number of 24 pack

s = number of 12 pack

 

24b + 12s = 108

12b + 18s = 66

 

Multiply bottom equation by 2 and subtract from top equation.

 

-24s = -24

s= 1.

 

Substitute into either equation and solve for b.

 

He bought 1 12-pack and 4 24-pack.

 

He bought 1 12-pack and