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. 10)
10.
The least multiple of 7, which leaves a remainder of 4, when divided by 6, 9, 15 and 18 is:
74
94
184
364
Answer: Option
Explanation:

L.C.M. of 6, 9, 15 and 18 is 90.

Let required number be 90k + 4, which is multiple of 7.

Least value of k for which (90k + 4) is divisible by 7 is k = 4.

Required number = (90 x 4) + 4   = 364.

Discussion:
88 comments Page 1 of 9.

Bhavesh said:   4 years ago
90K+4 is the required number.

If K=1,
90*1+4=94 , it is not multiple of 7.
90*2+4=184,it is not multiple of 7,
90*3+4=274,it is not multiple of 7,
90*4+4=364,it is multiple of 7,
So, the least value will be 364.
(61)

Nakum pragnesh said:   3 years ago
Or which option is divisible by 7 is your answer
(23)

Sagar Khare said:   4 years ago
@ALL.

Guys here you use divisibility rules.

We have to find 7 multiple so apply the simple divisibility rule of 7 on all the answers.
(23)

Navnath said:   4 years ago
As sample as that.

If the number is multiple of 7 then Obviously it should divide by 7.
Then check all the options by dividing 7.

Look only one option that is 364 is completely divided by 7.
(22)

Jeni said:   5 years ago
6 = 2,3.
9 = 3,3.
15 = 3,5.
18 = 2,3,3.
LCM = 7 x 2 x 3 x 3 x 5 = 360.
Add the reminder = 360 + 4 = 364.
(21)

MMTbelieve youtube said:   2 years ago
We got till lcm 90 ,
Then N=90k+4 should be divisible by 4 then we will get n.
So, put k=1,2,3,4 on 4 the ans 364 is divisible by 7.
So N = 364.
(15)

Jambay said:   5 years ago
Why we are taking LCM instead of GCF? Please explain.
(7)

Akash said:   4 years ago
@Jeni.

Can you please explain how came 7 when calculating the LCM?
(4)

SUBHANKAR DAS said:   4 years ago
L.C.M. of 6, 9, 15, and 18 is 90.
Let the required number be 90k + 4, which is a multiple of 7.
Least value of k for which (90k + 4) is divisible by 7 is k = 4,as it is not divisible if k=1,2,3
So, the Required number = (90 x 4) + 4 = 364.
(3)

Codi said:   3 years ago
Thanks for explaining @Rahul.
(2)


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