At the local pet store, zebra fish cost $1.80 each and neon tetras cost $2.10 each. If Ernesto bought 16 fish for a total cost of $30.90, not including tax, how many of each type of fish did he buy? Help ASAP!!

Accepted Solution

The number of each type of fish that Ernesto bought are 7 neon tetras and 9 zebra fishes.Let the zebra fish be Z.Let the neon tetras be N.Given the following data:Total cost = $30.90Total number of fishes = 16 fishes.To calculate the number of each type of fish that Ernesto bought: How to solve a word problem.First of all, we would assign a variable to each type of fish that Ernesto bought and then write a system of algebraic equations. Finally, we would solve the system of algebraic equations by using the substitution method.Translating the word problem into an algebraic expression, we have;[tex]Z+N=16[/tex]    .....equation 1.[tex]1.80Z+2.10N=30.90[/tex]   .....equation 2.From eqn. 1, we have:[tex]Z=16-N[/tex]      .....equation 3.Substituting eqn. 3 into eqn. 2, we have:[tex]1.80(16-N)+2.10N=30.90\\\\28.80-1.80N+2.10N=30.90\\\\28.80+0.30N=30.90\\\\0.30N=30.90-28.80\\\\0.30N=2.10\\\\N=\frac{2.10}{0.30}[/tex]N = 7 neon tetras.For the zebra fish:[tex]Z=16-N\\\\Z=16-7[/tex]Z = 9 zebra fishes.Read more on word problems here: