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. 1)
1.
Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case.
4
7
9
13
Answer: Option
Explanation:

Required number = H.C.F. of (91 - 43), (183 - 91) and (183 - 43)

     = H.C.F. of 48, 92 and 140 = 4.

Discussion:
210 comments Page 6 of 21.

Surbhi swaraj said:   1 decade ago
Is there any trick to solve this problem?

Heena said:   1 decade ago
Here take the difference between the numbers then start dividing.
48/2, 92/2, 140/2
Then
48/2=2*2*2*2*3
92/2=2*2*23
140/2=2*2*35

So HCF is [nothing but the highest common factor].
So HCFis 2*2=4.

Lovely said:   1 decade ago
Hey prashant your explanation is too good. Thanks.
Is there more short method to do solve this.

Aadhilakshmi said:   1 decade ago
Thanks for the clear explanation prasanth.

Parthiban said:   1 decade ago
It is very simple
consider
43,91,183 are the 3 numbers
first ,
find the diff between them
91-43=48;
183-91=92;
183-43=140;
let divide the 48,92,140,by 2
we have
48=2*2*2*2*3
92=2*2*23
140=2*2*149
here common factor is 2*2
so
answer is 4

Mayank said:   1 decade ago
4*22-gives rem 3.
4*10-gives rem3.
4*45-also gives rem 3.
All three numbers have equal rem 3 satisfies condition given in number. Hence ans is 4.

Cathy said:   1 decade ago
How do you know we are to find the h.C.F ?

I seem to be getting so confused.

Karthick said:   1 decade ago
@Cathy.

The keyword is greatest or largest- if you find these words, we are required to find HCF. If in case you find least or lowest in the problem, we need to find LCM.

Ankur jindal said:   1 decade ago
If three nos as in this case is 43, 91 and 183 are given then to find HCF the shortest solution is take the diff:

1) 91 - 43 = 48 (4*3*7).
2) 183 - 91 = 92 (4*23).
3) 183 - 43 = 140 (4*7*5).

Thus the HCF is 4.

Merry said:   1 decade ago
When pratibhan said the common factor is 2 ok this is write but why she multiple two no of 2 whyn't three no of 2 means the result is 8.


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