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:
200 comments Page 20 of 20.

Shwetha said:   1 decade ago
Simply divide each number by 4 the remainder is same for all so the answer is 4.

Hary said:   1 decade ago
Solving the equations:
91=pq2+r
43=pq1+r
_________________
48=pq2-pq1
thus
48=p(q2-q1)=91-43.

Sakthivel said:   1 decade ago
How to arrive at this equation p(q2-q1)= (91-43) from 43 = pq1 + r;
91 = pq2 + r;
183 = pq3 + r;

Prashant said:   1 decade ago
We can represent any integer number in the form of: pq+r.
Where p is dividend, q is quotient, r is reminder.

so: 43 = pq1 + r;
91 = pq2 + r;
183 = pq3 + r;

Take r same in above three equations as given in question.
p is the value that we want to find out. which should be greatest.

On solving three equations we get:

p(q2-q1)= (91-43)=48;
p(q3-q2)= (183-91)=92;
p(q3-q1)= (183-43)=140;

For the greatest value of p that divide each equation we take the HCF of 48,92,140

THEREFORE ANSWER IS 4.

Arya 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.

Anirudh rai said:   1 decade ago
Is this the only way to this type of problem?

If yes then would you please explain it.

Raj said:   1 decade ago
Why do we do the difference of number to each other?

Sourabh Das said:   1 decade ago
I also want an explanation about the logic of the solution.

Anu said:   1 decade ago
Explain the logic of this solution.

Nagu said:   1 decade ago
Why they took difference between those nos.

Please explain me.


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