What is the cost six filters if eight filters cost $39.92

Question

What is the cost of six filters if eight filters cost $39.92

Answer 1

Given:  8 filters cost $39.92

 

Find:  6 filters cost x

 

Set this up as a proportion.

 

8 → $39.92

6 → x

 

x = (6)($39.92) / 8 = $29.94

 

It costs $29.94 to buy 6 filters.

Answer 2

39.92 : 6 :: c : 8              proportion

6c = 8(39.92)                  product means/extremes

 

Can you solve for c?