In a zoo, the ratio of the number of cheetahs to the number

Consider the number of cheetahs = 10;...> no of pandas=30
Therefore if number of cheetas is 5 more=10+5=15 then pandas must be 3 times more=15*3=45.
Increase in the number of pandas=45-30=15

Ans-D

Hi All,

When a ratio question involves "relatively small" numbers, you can quickly "brute force" the prompt and get to the correct answer.

Here, we know the ratio of cheetahs to pandas is 1:3. Since you can't have a "fraction" of an animal, that means that the number of cheetahs is a multiple of 1 and the number of pandas is the equivalent multiple of 3.

Here is a quick list of the immediate possibilities....

C:P
1:3
1 and 3
2 and 6
3 and 9
4 and 12
5 and 15
6 and 18
Etc.

We're told that the ratio of cheetahs to pandas stayed the same and that over the last 5 years there was an increase of 5 cheetahs.

If we "start" with 1 cheetah and 3 pandas, then increase the number of cheetahs by 5.....we'll have 6 cheetahs and 18 pandas....Thus, the number of pandas increased from 3 to 18 (an increase of 15.

Final Answer:

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

Use simple logic:

Given the ratio 1:3, if you increase 1 by 5, you will need to increase 3 by 3*5 to retain the ratio

\(\frac{1}{3} = \frac{1 + x}{3 + 3x} = \frac{1(1+x)}{3(1+x)} = \frac{1}{3}\)

So, if you increase numerator by 5, denominator must be increased by 3*5 = 15

One simple logic would be;If two things are in ratio then over the period of time if there is any increment/decrement and even after that they maintain same ratio then increment/decrement will also be in the same ratio.

Now and 5 years back ratio is= 1:3
Increment in C= 5
Hence, Increment in P will be 15

Hope this helps !

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