Question

Write an expression to represent the total number of lemon tetras that could be in a 20 gallon aquariam

Answer 1

 I gallon of water per 1 inch of fish

 lemon tetra is 2 inches long

 so 1 lemon tetra for 2 gallons of water

20/2 = 10

 they can have 10 of them

 equation would be X = 20/2

Answer 2

Let t represent a number of lemon tetras allowed per gallon.

20t