zebra fish cost 1.95 each and neon tetras cost 2.40 each. Yumi bought 11 fish for a total cost of 23.25 how many of each type of fish did she buy?

Question

the answers are either :

a. 9 zebra fish, 2 neon tetras

b. 4 zebra fish, 7 neon tetras

c. 7 zebra fish, 4 neon tetras

d. 2 zebra fish, 9 neon tetras

Answer 1

Let x=number of zebras.  Then the number of tetras will be 11-x.  (The sum of x and 11-x is 11.)

 

(1.95)*x+(2.40)*(11-x)=23.25      * means "times" or "multiply by".

 

195*x+240*(11-x)=2325               Multiplied each side of the equation by 100 to get rid of decimal points.

 

195*x+2640-240x=2325                Multiplied 240 by (11-x).

 

195*x-240*x=2325-2640               Put all unknowns (the x's) on the left and all else on the right of the equals sign.

 

-45*x=-315                                   Combine like terms and simplify.

 

x=7 (the number of zebras)            Solving for x (divide 315 by 45; "a minus divided by a minus is a plus)

 

11-x=4  (the number of tetras)       The correct answer is c above.