Arithmatical - HCF and LCM of Numbers
DIRECTIONS : Problems based on HCF and LCM.
16. |
The product of two numbers is 4107. If the H.C.F of those numbers is 37, then the greater number is |
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A. 101 |
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B. 107 |
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C. 109 |
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D. 111 |
Solution |
Let the numbers be 37a and 37 b. Then, 37a ×37b = 4107 |
‹=› ab = 3. |
Now, co-primes with product 3 are (1, 3). |
So, the required numbers are (37 ×1, 37 ×3) i.e , (1 , 111) |
Therefore Greater number = 111. |
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17. |
The greatest possible length which can be used to measure exactly the length 7m, 3m 85cm, 12 m 95 cm is |
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A. 15 cm |
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B. 25 cm |
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C. 35 cm |
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D. 42 cm |
Solution |
Required length | = H.C.F of 700 cm, 385 cm and 1295 cm |
‹=› 35 cm. |
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18. |
Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case. |
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A. 4 |
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B. 7 |
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C. 9 |
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D. 13 |
Solution |
Required number |
= H.C.F of (91 - 43), (183 - 91) and (183 - 43) |
= H.C.F of 48, 92 and 140 |
= 4. |
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19. |
Let N be the greatest numbers that will divide 43, 91 and 183 so as to leave the same remainder in each case. |
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A. 4 |
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B. 7 |
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C. 9 |
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D. 13 |
Solution |
Required number | = H.C.F of (91 - 43), (183 - 91) and (183 - 43) |
= H.C.F of 48, 92 and 140 |
‹=› 4. |
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20. |
Product of two co-prime numbers is 117. Their L.C.M should be |
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A. 1 |
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B. 117 |
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C. equal to their H.C.F |
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D. cannot be calculated |
Solution |
H.C.F of co-prime numbers is 1. |
So, L.C.M | = 117/1 |
‹=› 117. |
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