MathStories.comTM

Sheet # 84 Critical Thinking

Name: _____________________ Date_____________

The students at Peterson High School are designing a small pond. They have decided to build the pond to hold 1000 gallons of water. They have also selected two kinds of fish to occupy their pond: Goldfish and Koi. Goldfish can grow up to 12 inches in length and Koi can reach a length of 24 inches. Both these breeds require 2 gallons of water per inch of fish length.

The students want to make sure they have an equal number of each kind of fish. Making sure they have enough space in the water for each fish, what is the maximum number of each breed they can purchase?

Goldfish = G

Koi = K

G = K

Each Goldfish needs 12 inches x 2 gallons = 24 gallons

Each Koi needs 24 inches x 2 gallons = 48 gallons

1) 24G + 48K = 1000 gallons

Also number of Goldfish is equal to number of Koi fish. G = K

Using this and #1 equation

24G + 48G = 1000

72G = 1000

G = 13.88
K = 13.88

So number of Goldfish = 13.
Number of Koi fish = 13

If you use 14, the total amount of water will exceed 1000 gallons.