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. 21)
21.
The greatest possible length which can be used to measure exactly the lengths 7 m, 3 m 85 cm, 12 m 95 cm is:
15 cm
25 cm
35 cm
42 cm
Answer: Option
Explanation:

Required length = H.C.F. of 700 cm, 385 cm and 1295 cm = 35 cm.

Discussion:
42 comments Page 4 of 5.

Pritam said:   10 years ago
Could not understand why HCF not LCM?

Renuka said:   1 decade ago
Thank you friends.

Gopi krishna said:   1 decade ago
How we can find factors for such numbers?

NareshBora said:   1 decade ago
Easy process to find HCF is

7m = 7*100 = 700cm.

3m85cm = 3*100+85 = 385cm.
12m95cm = 1200+95 = 1295cm.

Given lengths in cm are 700, 385, 1295

Now 700-385 = 315.

1295-385 = 910.
1295-700 = 595.

Factors for 315 = 7*5*3*3.

910 = 7*5*2*13.
595 = 7*5*17.

Common Highest factor is 7*5 = 35.

So, answer is 35.
(13)

146 said:   1 decade ago
Please give me the prime factors of 1295.

145 said:   1 decade ago
As we need to find out greatest possible length as mentioned in the queue. We need to find out HCF and not LCM.

Nikhil said:   1 decade ago
Why it is HCF? why not LCM?

Please explain.

111 said:   1 decade ago
Thanks raviteja

111 said:   1 decade ago
Thanks Ravireja

Raviteja said:   1 decade ago
Required length = H.C.F. of 700 cm, 385 cm and 1295 cm.
385)700(1
385
---
315)385(1
315
---
70)315(4
280
---
35)70(2
70
--
x

35)1295(37
1295
----
X
----
i.e., H.C.F. of 700 cm, 385 cm and 1295 cm = 35 cm.


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