# 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 ?

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:

49 comments Page 1 of 5.
Mayur said:
3 years ago

First find LCM Of denominator;

LCM of 8,16,40,80=80

Now let's same all the denominator

7*10/8*10. = 70/80.

13*5/16*5. = 65/80.

31*2/40*2 62/80.

63*1/80*1. 63/80.

As u can see all the denominators is the same,

So see numerator now 70/80 { 70 is biggest}

Which means

7/8 Is the largest fraction.

LCM of 8,16,40,80=80

Now let's same all the denominator

7*10/8*10. = 70/80.

13*5/16*5. = 65/80.

31*2/40*2 62/80.

63*1/80*1. 63/80.

As u can see all the denominators is the same,

So see numerator now 70/80 { 70 is biggest}

Which means

7/8 Is the largest fraction.

(9)

Kriti said:
6 years ago

As per my knowledge, the fraction whose denominator is the smallest is the largest fraction.

(4)

Ajkniu said:
5 years ago

As per my knowledge, the fraction whose denominator is the smallest is the largest fraction.

(2)

Vishwanath said:
6 years ago

Since there denominators are divisible by 8, simplify them into.

7/1, 13/2, 31/5, 63/10.

After solving them, it's clear that 7 is the largest.

7/1, 13/2, 31/5, 63/10.

After solving them, it's clear that 7 is the largest.

(2)

Vaibhav said:
8 years ago

Hello, guys.

The lcm is 80. So we have to make 80 as the base for all numbers. In this example, if we want to make base 80 for no 7/8 we have to multiply the N and D by 10. For 13/16 for base 80-multiply N and D by 5. For 31/40 for making base 80 multiply N and D by 2. And 4rth no already has base 80 so we don't need anything to do.

The lcm is 80. So we have to make 80 as the base for all numbers. In this example, if we want to make base 80 for no 7/8 we have to multiply the N and D by 10. For 13/16 for base 80-multiply N and D by 5. For 31/40 for making base 80 multiply N and D by 2. And 4rth no already has base 80 so we don't need anything to do.

(2)

Khagendra said:
7 years ago

Awesome shortcut, thanks @Sarah.

(1)

Sarah said:
8 years ago

LCM of 8, 16, 40 and 80 is 80 then,

80/8 = 10.

80/16 = 5.

80/40 = 2.

80/80 = 1 then,

7/8 * 10/10 = 70/80.

13/16 * 5/5 = 65/80.

31/40 * 2/2 = 62/80.

63/80 * 1 = 63/80.

70/80 > 65/80 >63/80 > 62/80.

So 7/8 is largest.

80/8 = 10.

80/16 = 5.

80/40 = 2.

80/80 = 1 then,

7/8 * 10/10 = 70/80.

13/16 * 5/5 = 65/80.

31/40 * 2/2 = 62/80.

63/80 * 1 = 63/80.

70/80 > 65/80 >63/80 > 62/80.

So 7/8 is largest.

(1)

Amita said:
10 years 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.

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.

Glory said:
10 years ago

Hi guys,

Which one is correct in simple way am confused with your solutions, I need to understand how to use L.C.M in solving that question?

Which one is correct in simple way am confused with your solutions, I need to understand how to use L.C.M in solving that question?

Deepti said:
10 years ago

The answer given by @Hanumanth is not applicable to all kinds of questions with same nature. I have tried. Its wrong.

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