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 ?
Answer: Option
Explanation:
L.C.M. of 12, 18, 21 30 2 | 12 - 18 - 21 - 30
----------------------------= 2 x 3 x 2 x 3 x 7 x 5 = 1260. 3 | 6 - 9 - 21 - 15
----------------------------Required number = (1260 รท 2) | 2 - 3 - 7 - 5
= 630.Discussion:
31 comments Page 3 of 4.
Rajesh said:
10 years ago
The double of 1260 = 158760 is also divisible by 12, 18, 21, 30.
So, why can't option (c) 1260 be the answer?
So, why can't option (c) 1260 be the answer?
Aasritha said:
10 years ago
Thank you Parnassus for it. I didn't understand it first.
Appalaraju said:
1 decade ago
Because it is already considered as it doubled in question only so please read questions and ask your doubts 630 is right answer.
Teja said:
1 decade ago
Here, they have given number "which when doubled ", which mean 1260 /2 = 630.
Aadhithyaa said:
1 decade ago
They have told that the required number= (1260/2) = 630, where did that to which divides 1260 come from?
Shreya said:
1 decade ago
Because it is already considered as it is doubled in the question that means the lcm is the doubled digit, therefore we divide it by 2 so as to get the least number.
Akshara said:
1 decade ago
Double in actual means x*x i.e x^2. The question is perceived as x*2.
Deepak said:
1 decade ago
1260/2 come ,because in Q it ask to find least no.(630) which when double to divisible by given no.(12,18,21,30)
Grishma said:
1 decade ago
How 1260/2 comes?
Priz said:
2 decades ago
Thanks Aparna, it is really helpful
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