Numbers - General Questions (5)
| 33. | On multiplying a number by 7, the product is a number each of whose digits is 3. The smallest such number is: |
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Answer: Option A Explanation: By hit and trial, we find that 47619 x 7 = 333333. |
| 34. | 2056 x 987 = ? |
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Answer: Option B Explanation:
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| 35. | If the number 91876 * 2 is completely divisible by 8, then the smallest whole number in place of * will be: |
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Answer: Option C Explanation: Then number 6x2 must be divisible by 8.
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x = 3, as 632 is divisible 8.| 36. | The sum of even numbers between 1 and 31 is: |
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Answer: Option C Explanation: Let Sn = (2 + 4 + 6 + ... + 30). This is an A.P. in which a = 2, d = 2 and l = 30 Let the number of terms be n. Then, a + (n - 1)d = 30
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2 + (n - 1) x 2 = 30| 37. |
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Answer: Option B Explanation:
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| 38. | In a division sum, the remainder is 0. As student mistook the divisor by 12 instead of 21 and obtained 35 as quotient. What is the correct quotient ? |
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Answer: Option D Explanation: Number = (12 x 35) Correct Quotient = 420 � 21 = 20 |
| 39. | 9548 + 7314 = 8362 + (?) |
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Answer: Option C Explanation: 9548 16862 = 8362 + x + 7314 x = 16862 - 8362 ----- = 8500 16862 ----- |
| 40. | If x and y are positive integers such that (3x + 7y) is a multiple of 11, then which of the following will be divisible by 11 ? |
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Answer: Option D Explanation: By hit and trial, we put x = 5 and y = 1 so that (3x + 7y) = (3 x 5 + 7 x 1) = 22, which is divisible by 11.
(x + y + 4 ) = (5 + 1 + 4) = 10, which is not divisible by 11; (9x + 4y) = (9 x 5 + 4 x 1) = 49, which is not divisible by 11; (4x - 9y) = (4 x 5 - 9 x 1) = 11, which is divisible by 11. |