Multiple choice

A school library has 3,000 books, 15% of which are encyclopedias. The school management is planning to increase the number of books in the library by another 20%. How many new encyclopedias must be added in the new collection in order to increase the percent of encyclopedias to 20%?

  1. 270

  2. 280

  3. 290

  4. 300

  5. 315
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A Correct answer
Explanation

Initial encyclopedias = 15% of 3000 = 450. Total books after 20% increase = 3000 * 1.2 = 3600. To have 20% of 3600 as encyclopedias, we need 0.2 * 3600 = 720 encyclopedias. The number of new encyclopedias required is 720 - 450 = 270.

AI explanation

The new total number of books will be 3000 * 1.2 = 3600. To make encyclopedias 20% of this new total, the library needs 3600 * 0.2 = 720 encyclopedias. Since the library initially has 3000 * 0.15 = 450 encyclopedias, it must add 720 - 450 = 270 new encyclopedias.

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