Question: What will be the least number which when doubled will be exactly divisible by 12, 18, 21 and 30 ?
[A].196
630
1260
2520
[A].
[B].
[C].
[D].
Answer: Option B
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 2) | 2 – 3 – 7 – 5
= 630.