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. 19)
19.
The smallest number which when diminished by 7, is divisible 12, 16, 18, 21 and 28 is:
1008
1015
1022
1032
Answer: Option
Explanation:

Required number = (L.C.M. of 12,16, 18, 21, 28) + 7

   = 1008 + 7

   = 1015

Discussion:
28 comments Page 1 of 3.

AJAY said:   2 years ago
The answer is wrong correct answer is;.
Lcm (12, 16, 18, 21, 28) = 504 +7.
= 511.
(1)

Jagruti said:   4 years ago
Easy and short method:

As given in question when 7 is subtracted from a number, the number is divisible by 12,16,18, and so on;

So with the help of the given option;

1008 - 7 =1001 which is not divisible by 12 (use 12 because as given in question, the number is divisible by 12,16,18)

1015 -7 = 1008 which is divisible by 12.

So the answer is 1015.
(7)

Abhi said:   4 years ago
1015 which when diminished(subtracted) by 7 i.e.1008 this number will divisible by 12,16,18,21,28. so answer is 1015.

LCM of (12,16,18,21,28) = 1008.
(1)

Sravani said:   5 years ago
How to get the lcm 1008?

Please explain in detail.
(1)

Ashwin said:   6 years ago
simple trick guys,

1+0+1+5 = 7.
and 7/7 = 0 (reminder).

So, the answer is 1015.
(5)

Maneesha said:   7 years ago
Least number = x
Then x-7 = lcm of 12, 16, 18, 21, 28.
x-7 = 1008,
x = 1008 + 7,
x = 1015.
(9)

Sunny Agrawal said:   7 years ago
So,

Let assume that the smallest number is X. And it diminished by 7 so it will be like
= X-7.

Now, this number is divisible by 12, 16, 18, 21, 28 and also it is divisible by LCM OF them.
So the LCM = 1008.
So now,
X-7/1008 = 1.
X = 1015.

Hope it helps.
(2)

Aswani Reddy said:   7 years ago
How it comes 1008?

Avinash said:   7 years ago
But 1015 is not divided by 21. Am I right?

Akshay said:   7 years ago
How it comes 1008?


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