11.

The sum of first five prime numbers is:

 A. 11 B. 18 C. 26 D. 28
Explanation: Required sum = (2 + 3 + 5 + 7 + 11) = 28.

Note: 1 is not a prime number.

Definition: A prime number (or a prime) is a natural number that has exactly two distinct natural number divisors: 1 and itself.

12.

The difference of two numbers is 1365. On dividing the larger number by the smaller, we get 6 as quotient and the 15 as remainder. What is the smaller number ?

 A. 240 B. 270 C. 295 D. 360
Explanation: Let the smaller number be x. Then larger number = (x + 1365).

x + 1365 = 6x + 15

5x = 1350

x = 270

Smaller number = 270.

13.

72519 x 9999 = ?

 A. 725117481 B. 674217481 C. 685126481 D. None of these
Explanation: 72519 x 9999 = 72519 x (10000 - 1)

= 72519 x 10000 - 72519 x 1

= 725190000 - 72519

= 725117481.

14.

If the number 517 * 324 is completely divisible by 3, then the smallest whole number in the place of * will be:

 A. 0 B. 1 C. 2 D. None of these
Explanation: Sum of digits = (5 + 1 + 7 + x + 3 + 2 + 4) = (22 + x), which must be divisible by 3.

x = 2.

15.

The smallest 3 digit prime number is:

 A. 103 B. 107 C. 113 D. None of these