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:
30 comments Page 2 of 3.
Sanjana said:
6 years ago
Let the number Be N.
Then LCM of 12,18,21,30 is 1260and given that 2N/1260 leaves no remainder.
Now, N/630 this means we have to find the least value of N from options which when divided by 630 leaves no remainder.
Although, options b, c, d leaves no remainder when divided by 630 we had been asked the least value of N, so option 2 i.e., 630 is the answer
Then LCM of 12,18,21,30 is 1260and given that 2N/1260 leaves no remainder.
Now, N/630 this means we have to find the least value of N from options which when divided by 630 leaves no remainder.
Although, options b, c, d leaves no remainder when divided by 630 we had been asked the least value of N, so option 2 i.e., 630 is the answer
Preksha Darshan said:
6 years ago
630 is the right answer.
Braj said:
6 years ago
The correct answer is 1260.
CHINMAYEE said:
7 years ago
If triple then 3 is diveded.
Abhilash said:
7 years ago
@Mobin.
The easiest way of finding HCF for eg; 12, 18, 21, 30
Ans : 3.
First, see the least difference between any two numbers, suppose between 18 and 21, the diff is 3.
Now see if 12,18,21,30 are divisible by 3. If divisible then 3 is the answer.
The easiest way of finding HCF for eg; 12, 18, 21, 30
Ans : 3.
First, see the least difference between any two numbers, suppose between 18 and 21, the diff is 3.
Now see if 12,18,21,30 are divisible by 3. If divisible then 3 is the answer.
Saras said:
1 decade ago
why we are dividing by 2?? pl tel me and also tel me some easy tricks for h c m and l c m
Govind said:
8 years ago
Thanks for the given explanation.
Tinku said:
8 years ago
Thanks for the explanation.
Ritesh said:
9 years ago
Why divided by 2, in L.C.F?
Rajesh said:
9 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?
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