Question

A shopkeeper has 21 books. If he puts 3 books in one box then he will need boxes.

• A. 8
• B. 9
• C. 7

Answer 1

The correct option is C 7

Total number of books = 21
Number of books in 1 box = 3
Total number of boxes required can be obtained by dividing 21 by 3.
Lets apply repeated subtraction method.

21 - 3 = 18
18 - 3 = 15
15 - 3 = 12
12 - 3 = 9
9 - 3 = 6
6 - 3 = 3
3 - 3 = 0

After 7 times 21 reduces to 0.

So, Number of boxes required will be 7.