Arithmetic, Percent and Interest Problems

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Arithmetic, Percent and Interest Problems

by swerve » Wed May 13, 2020 3:13 pm

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A

B

C

D

E

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Poetry books make up what percent of the books on Beth’s bookshelf?

1) Of the 60 books on Beth’s bookshelf, 15 are novels.
2) There are 12 poetry books on Beth’s bookshelf.

The OA is C

Source: Princeton Review
Source: — Data Sufficiency |

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C

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Statement 1=> Of the 60 books on Beth's bookshelf, 15 are novels

Total number of books = 60
Total number of novels = 15
Total number of poetry = ??

Since the exact value of poetry books on the bookshelf is unknown, we cannot estimate it's percent.
Statement 1 is NOT SUFFICIENT

Statement 2 => There are 12 poetry books on Beth's bookshelf
$$\%\ of\ poetry\ books\ =\frac{12}{total\ number\ of\ books}\cdot\frac{100}{1}$$
But total number of books is unknown hence statement 2 is NOT SUFFICIENT

Combining both statements together =>
Total number of books = 60
Total number of poetry books = 12
$$\%\ of\ poetry\ books\ =\frac{12}{60}\cdot\frac{100}{1}$$
$$=20\%$$

Both statements combined together ARE SUFFICIENT

Answer = C