The aquarium has 3 more yellow fish than green fish. 60 percent of the fish are yellow. How many green fish are in the aquarium? Show your work

9514 1404 393

  6

Step-by-step explanation:

If 60% are yellow, the other 40% are green. Then the difference between yellow and green is 60% -40% = 20% of the total number of fish. That difference also happens to be half of the number of green fish:

  20% = (1/2)(40%)

So, the number of green fish is 2×3 = 6.

If you wanted to, you could write a couple of equations:

  y - g = 3

  y = 0.60(y +g)

Using the first equation to write an expression for y, we get ...

  y = g +3

Using this in the second equation, we have ...

  g +3 = 0.6(g +3 +g)

  g +3 = 1.2g +1.8 . . . . eliminate parentheses

  1.2 = 0.2g . . . . . . . .  subtract g+1.8

  1.2/0.2 = g = 6 . . . . . divide by 0.2

There are 6 green fish in the aquarium.