# Algebra

posted by on .

A quarium has a total of 28 beta fish, piranhas, and turtles. The number of piranhas is 1 more than the number of turtles, and 2 fewer than the number of beta fish. How many beta fish are there in the aquarium?

• Algebra - ,

It's a system of equations problem. Just represent the values with different expressions as they relate.

givens:

28 animals total

number of piranhas = 1 more than turtles

number of piranhas = 2 less than number of beta fish

let x = number of piranhas

piranhas = x

turtles = x - 1 (there's one less turtle)

number of beta fish = x + 2 (there are two more beta fish than piranhas)

now you can put all the expressions together and equate it to the total number of creatures in the tank.

x + x - 1 + x + 2 = 28

simplifies to 3x + 1 = 28

now solve for x

3x + 1 = 28
-1 -1
3x = 27
/3 /3

x = 9

now plug this value in the expression you used to represent the beta fish --
(x + 2)

x = 9 so 9 + 2 = 11

there are 11 beta fish in the aquarium