Question

On a fish tank 1/5 of the fish are guppies and 1/12of the fish are gold fish.Which equation most closely estimates the fraction of the fish that are guppies or goldfish in the fish tank

Answer 1

Answer: 17/60

Explanation:

Suppose that whe have N fishes.

We know that 1/5 of these N fishes are guppies.

We also know that 1/12 of these N fishes are goldfish.

Now, what is the fraction of guppies and goldfish together?

We only need to add the fractions:

1/5 + 1/12

This may be hard because the denominators are different, then the first step will be to write both fractions with the same denominator.

We know that:

5*12 = 60

Then we can write:

1/5 = (12/12)*(1/5) = 12/(5*12) = 12/60

and

1/12 = (5/5)*(1/12) = 5/(5*12) = 5/60

Then our previous sum:

1/5 + 1/12

can be written as:

12/60 + 5/60

and this is easy to solve:

12/60 + 5/60 = (12 + 5)/60 = 17/60

This is the fraction of the fish that are guppies or goldfish.