Aptitude - Problems on H.C.F and L.C.M - Discussion

Discussion Forum : Problems on H.C.F and L.C.M - General Questions (Q.No. 17)
17.
What will be the least number which when doubled will be exactly divisible by 12, 18, 21 and 30 ?
196
630
1260
2520
Answer: Option
Explanation:

L.C.M. of 12, 18, 21 30 2 | 12 - 18 - 21 - 30

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= 2 x 3 x 2 x 3 x 7 x 5 = 1260. 3 | 6 - 9 - 21 - 15

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Required number = (1260 รท 2) | 2 - 3 - 7 - 5

= 630.
Discussion:
31 comments Page 4 of 4.

Ravithe said:   1 month ago
The answer is 630 only.

Because they have asked the least number when doubled, and they have not said that the least number should also be divisible by the given numbers.

If they have asked, then the answer will be double the LCM. So the answer is 630.


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