9514 1404 393
Answer:
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.
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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.
