Question

Solve the following question and mark the most appropriate option.
x is a natural number between 1 and 20, both inclusive, such that

1. If x is even, then it is also a multiple of 3.
2. If x is not a multiple of 3, then it is greater than the length of the diagonal of a square with an area of 81.
3. If x is not greater than the length of the diagonal of a square with an area of 81, then it is square.
4. If x is not a perfect square, then it is one greater than a multiple of 5.

What is the value of x?

विकल्प

• 6

• 12

• 9

• 15

Answer 1

From the first condition, if x is even, then x = 6, 12 or 18, otherwise it is 1, 3, 5, 7, 9, 11, 13, ..., 19.
From the second and third conditions, if x is greater than 9√2, then x = 13, 14, 16, 17, 19 or 20, otherwise it is 9, 15, 18.
From the fourth condition, if x is not a perfect square, then x = 6 or 11 otherwise it is 1, 4, 9 & 16.
The only value that satisfies all the above conditions is x = 9.