At a certain zoo, the ratio of sea lions to penguins is 4 to 11. If th

Hi All,

Ratio questions will appear on Test Day in a variety of 'formats', but the basic rules behind ratios stay the same - so you can use those rules to your advantage and answer these types of prompts in a variety of different ways.

We're told that the ratio of sea lions to penguins is 4 to 11. This means that the number of sea lions MUST be a multiple of 4 the number of penguins MUST be an equivalent multiple of 11.

So we could have...
4 sea lions and 11 penguins
8 sea lions and 22 penguins
12 sea lions and 33 penguins
Etc.

Using those same examples, notice what happens to the DIFFERENCE in the number of animals...

4 sea lions and 11 penguins --> difference = 7
8 sea lions and 22 penguins --> difference = 14
12 sea lions and 33 penguins --> difference = 21
Etc.

Thus, the difference is an increasing multiple of 7

Next we're told that there are 84 more penguins than sea lions at the zoo. We're asked how many sea lions there are.

84 is a multiple of 7 --> 84/7 = 12

Thus there are 4(12) = 48 sea lions and 11(12) = 132 penguins

Final Answer:

GMAT assassins aren't born, they're made,
Rich