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. 24)
24.
Which of the following fraction is the largest ?
7
8
13
16
31
40
63
80
Answer: Option
Explanation:

L.C.M. of 8, 16, 40 and 80 = 80.

7 = 70 ;   13 = 65 ;   31 = 62
8 80 16 80 40 80

Since, 70 > 65 > 63 > 62 , so 7 > 13 > 63 > 31
80 80 80 80 8 16 80 40

So, 7 is the largest.
8

Discussion:
50 comments Page 2 of 5.

Saumyojit Das said:   7 years ago
Why we are taking out LCM why not HCF?

HCF will also give a common factor in the denominator.
(1)

Md. Khurshid said:   1 decade ago
I think @Hanumanth is right, because it is easiest way to check the correct answer that which fraction is larger or smaller.

Rakesh said:   1 decade ago
7/8=70/80, 13/16=65/80, 31/40=62/80 this answer how to come?

Asif said:   1 decade ago
I think @Vijaya is right, because it is easiest to check the correct answer that which fraction is larger or smaller.

Amita said:   1 decade ago
(a) 7/8 (b) 13/16 (c) 31/40 (d) 63/80.

First of all I compare b/t a and b with cross multiplication.

7/8, 13/16.

7*16 13*8.

112 >104.

So 7/8>13/16.

Again compare b/t 7/8 and 31/40.

7*40 31*8.

280 > 248, so 7/8>31/40.

Again compare b/t 7/8 and 63/80.

7*80 8*63.

560 > 504, so 7/8>63/80.

So 7/8 is largest.

Sikha said:   1 decade ago
I don't understand how we are getting 7/8 = 70/80.

13/16=65/80.
31/40=62/80.

Please somebody explain me dis?

Deepti said:   1 decade ago
The answer given by @Hanumanth is not applicable to all kinds of questions with same nature. I have tried. Its wrong.

Arts ashokan said:   1 decade ago
(7/8)*10 = 70/80;
(13/16)*5 = 65/80;
(31/40)*2 = 62/80;

Manik sharma said:   1 decade ago
I don't understand how 7/8 = 70/80?

Pritam said:   1 decade ago
How the LCM will be 80?


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