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 1 of 5.

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)

Jitan said:   2 years ago
Why we multiply 700 with 385?

Anyone, explain this step in detail?
(5)

Sanjay said:   6 years ago
Can anyone explain me clearly to get it?
(5)

Archit said:   8 years ago
It is very simple.

Just check the options , if any option is not divisible by any length then you can rule out that option.

Suppose 15 =3*5 where 3 is not divisible by 700 so it's not the right option.
Now 25 is not divisible by 385 so it is also ruled out,
Now 35 =7*5 which can be divided by all,
And last 42 (is even will give even multiple) which is also not divisible by 385 and you don't even have to check for the last one.
(3)

Mouni said:   4 years ago
HCF of 551 and 1073 = 29+19+27 = 85.
(2)

Sagat said:   5 years ago
Thank you all for explaining.
(2)

Aparna said:   1 decade ago
Don't worry its very easy

Whenever in the question,words like greatest or measurement or length comes,it is an HCF question
look at the options
the answers are in cm,so convert in cm all the values

e.g:
3m 85cm

1m=100cm
3m=?

we get,300cm
just add 85 in this,but don't do mutiplication
i:e
300+85=385

similarly,do with other nos.
and further find its HCF
(1)

Tessa said:   9 years ago
We need a length which can be used to measure the three given Lengths.

So it should be a common factor of all three numbers nd it should be the greatest also. So it's clearly highest common factor or HCF.
(1)

Ramboo said:   10 years ago
Because question says greatest possible length.
(1)

Sanjeev said:   7 years ago
Why did you consider 385 and 700 only?
(1)


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