Question

3 markers cost $5.79.

Which equation would help determine the cost of 13 markers?
Choose 1 answer:
A.) 13/$5.79 = x/3
B.) x/13 = 3/$5.79
C.) 3/$5.79 = 13/x
D.)13/x = $5.79/3
E.) None of the above

Answer 1

C. 3/$5.79 = 13/x

Explanation:

We can write the fact that 3 markers cost $5.79 as a proportion:

3/$5.79

Let x represent the unknown cost of 13 markers. Since 13 markers cost x, we have the following proportion:

13/x

The cost changes along with the number of markers purchased, and so the two proportions are equivalent.

3/$5.79 = 13/x