Question

Christiana wants to buy some miniature goldfish. She reads that a 9-gallon aquarium is a right size for 3 miniature goldfish. The graph represents this relationship.

Answer 1

The problem says the right size for 3 miniature goldfish is a 9-gallon aquarium, then the ratio is:

$\frac{3\text{ miniature goldfish}}{9-\text{gallon aquarium}}$

If we divide the numerator and the denominator by 3, we will obtain:

$\frac{3/3}{9/3}=\frac{1}{3}$

Thus, we need 3-gallon for each 1 miniature goldfish, then in the options we can see two that apply:

$\frac{6}{18}=\frac{6/6}{18/6}=\frac{1}{3}$

Then (6,18) is one of the options

The other one is (1,3) because it fits the ratio.

Answer: option A. (6,18) and option D. (1,3)