1. | If the sum of two numbers is 55 and the H.C.F. and L.C.M. of these numbers are 5 and 120 respectively, then the sum of the reciprocals of the numbers is equal to: |
||||||||||||||||||||||
Answer: Option C Explanation: Let the numbers be a and b. Then, a + b = 55 and ab = 5 x 120 = 600.
|
2. |
|
|||||||||||||
Answer: Option C Explanation:
|
3. | The L.C.M. of two numbers is 48. The numbers are in the ratio 2 : 3. Then sum of the number is: |
|||||||
Answer: Option C Explanation: Let the numbers be 2x and 3x. Then, their L.C.M. = 6x. So, 6x = 48 or x = 8.
Hence, required sum = (16 + 24) = 40. |
4. | Which of the following has the most number of divisors? |
|||||||
Answer: Option C Explanation: 99 = 1 x 3 x 3 x 11 101 = 1 x 101 176 = 1 x 2 x 2 x 2 x 2 x 11 182 = 1 x 2 x 7 x 13 So, divisors of 99 are 1, 3, 9, 11, 33, .99 Divisors of 101 are 1 and 101 Divisors of 176 are 1, 2, 4, 8, 11, 16, 22, 44, 88 and 176 Divisors of 182 are 1, 2, 7, 13, 14, 26, 91 and 182. Hence, 176 has the most number of divisors. |
5. | The greatest number which on dividing 1657 and 2037 leaves remainders 6 and 5 respectively, is: |
|||||||
Answer: Option B Explanation: Required number = H.C.F. of (1657 - 6) and (2037 - 5) = H.C.F. of 1651 and 2032 = 127. |
6. | The least number, which when divided by 12, 15, 20 and 54 leaves in each case a remainder of 8 is: |
|||||||
Answer: Option D Explanation: Required number = (L.C.M. of 12, 15, 20, 54) + 8 = 540 + 8 = 548. |
7. | Which of the following fraction is the largest ? |
||||||||||||||||||||||||||||||||||||||||||||||||||||
Answer: Option A Explanation: L.C.M. of 8, 16, 40 and 80 = 80.
|
8. | Find the highest common factor of 36 and 84. |
|||||||
Answer: Option C Explanation: 36 = 22 x 32 84 = 22 x 3 x 7
|