A certain aquarium holds three types of fish: angelfish, swordtails and guppies. What is the ratio of the number of...

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Magoosh

A certain aquarium holds three types of fish: angelfish, swordtails and guppies. What is the ratio of the number of guppies to the number of angelfish?

1) There are 200 fish in the aquarium
2) 45 percent of the fish are swordtails, and there are twice as many swordtails as there are angelfish

OA B

[Brent@GMATPrepNow]

Magoosh

A certain aquarium holds three types of fish: angelfish, swordtails and guppies. What is the ratio of the number of guppies to the number of angelfish?

1) There are 200 fish in the aquarium
2) 45 percent of the fish are swordtails, and there are twice as many swordtails as there are angelfish

OA B

Given: A certain aquarium holds three types of fish: angelfish, swordtails, and guppies.

Target question: What is the ratio of the number of guppies to the number of angelfish?

Statement 1: There are 200 fish in the aquarium.
Since we are not giving any information about the number of each type of fish, statement 1 is NOT SUFFICIENT

Statement 2: 45 percent of the fish are swordtails, and there are twice as many swordtails as there are angelfish.
There are twice as many swordtails as there are angelfish. 45% ÷ 2 = 22.5%
So, 45% are swordtails and 22.5% are angelfish.

Since all three percentages must add to 100%, we can conclude that the remaining 32.5% are guppies.
We can write: swordtails : angelfish : guppies = 45 : 22.5 : 32.5
The answer to the target question is the ratio of guppies to angelfish = 32.5 : 22.5
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent