Exercise :: Numbers - General Questions
- Numbers - Important Formulas
- Numbers - General Questions
| 11. | 5358 x 51 = ? |
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Answer: Option A Explanation:
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| 12. | The sum of first five prime numbers is: |
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Answer: Option D 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. |
| 13. | 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 ? |
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Answer: Option B Explanation: Let the smaller number be x. Then larger number = (x + 1365).
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x + 1365 = 6x + 15
5x = 1350| 14. | (12)3 x 64 ÷ 432 = ? |
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Answer: Option A Explanation:
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| 15. | 72519 x 9999 = ? |
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Answer: Option A Explanation:
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| 16. | If the number 517*324 is completely divisible by 3, then the smallest whole number in the place of * will be: |
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Answer: Option C Explanation: Sum of digits = (5 + 1 + 7 + x + 3 + 2 + 4) = (22 + x), which must be divisible by 3.
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| 17. | The smallest 3 digit prime number is: |
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Answer: Option A Explanation: The smallest 3-digit number is 100, which is divisible by 2.
101 < 11 and 101 is not divisible by any of the prime numbers 2, 3, 5, 7, 11.
Hence 101 is the smallest 3-digit prime number. |
| 18. | Which one of the following numbers is exactly divisible by 11? |
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Answer: Option D Explanation: (4 + 5 + 2) - (1 + 6 + 3) = 1, not divisible by 11. (2 + 6 + 4) - (4 + 5 + 2) = 1, not divisible by 11. (4 + 6 + 1) - (2 + 5 + 3) = 1, not divisible by 11. (4 + 6 + 1) - (2 + 5 + 4) = 0, So, 415624 is divisible by 11. |
| 19. | (?) - 19657 - 33994 = 9999 |
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Answer: Option A Explanation: 19657 Let x - 53651 = 9999 33994 Then, x = 9999 + 53651 = 63650 ----- 53651 ----- |
| 20. | The sum of first 45 natural numbers is: |
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Answer: Option A Explanation: Let Sn =(1 + 2 + 3 + ... + 45). This is an A.P. in which a =1, d =1, n = 45.
= 45 x (20 + 3) = 45 x 20 + 45 x 3 = 900 + 135 = 1035. Shorcut Method:
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