Question

At the local pet store, zebrafish cost $2.10 each, and neon tetras cost $1.95 each. if ernesto bought 13 fish for a total cost of $26.70 not including tax, how many of each type of fish did he buy?

Answer 1

• zebrafish: 9
• neon tetras: 4

Explanation:

The numbers of zebrafish and neon tetras can be found by writing an equation relating the numbers of each to their total cost.

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setup

Let z represent the number of zebrafish Ernesto bought. Then the number of neon tetras is (13 -z), and the total cost of the purchase was ...

2.10z +1.95(13 -z) = 26.70

solution

0.15z +25.35 = 26.70 . . . . . . simplify

0.15z = 1.35 . . . . . . . . . . . . subtract 25.35

z = 9 . . . . . . . . . . . . . . . divide by 0.15

Ernesto bought 9 zebrafish and 4 neon tetras.