Aptitude - Decimal Fraction - Discussion

@All.

Here, we can use

Smaller the numerator, the smaller the fraction, and vice versa.

Alternative methods for lesser variables:

1. If the denominator is less than 10, then directly divide and arrange
2. Cross multiplication can lead to check for LHS and RHS of options in required order.

Arrange numerators in ascending order and then write their corresponding denominators like this:

1/3, 2/5, 3/7, 4/5, 5/6, 6/7.

Now, if you carefully observe, numerator increases by +1 and denominator increases by +2.

In such case, when numerators and denominators increase by some value and for each fraction of that value is same, then greater the numerator, greater will the fraction and smaller the numerator, smaller will be the fraction.

Hence, here arranging in descending order,

6/7> 5/6> 4/5> 3/7> 2/5> 1/3.

Make denominator same;

Option D.

= 6*30/7*30, 5*35/6*35, 4*42/5*42, 3*30/7*30, 2*42/5*42, 1*70/3*70.
= 180/210 ,175/210 ,168/210 ,90/210 ,84/210 ,70/210.
Arrange the numerator in descending order.

For every positive value of n.
n/(n+1) is the largest value in the given values.

If the given fractions,the numerators are increasing by a definite value and the denominator is also increasing by a definite value but the value of denominator is greater than numerator, then the fraction having smaller numerator will be smallest fraction and the fraction having larger numerator will be largest fraction..

6/7 = 0.857.
5/6 = 0.833.
4/5 = 0.8.
3/7 = 0.42.
2/5 = 0.4.
1/3 = 0.333.
Then the option "D" is correct.

I think these fractions can be compared by cross multiplication method or by making all the denominators the same like using lcm as a multiplication factor.

Simply Multiply all value with 100 so that you will get the answers regarding 100
like 1/3*100, 2/5*100, 3/7*100, 4/5*100, 5/6*100, 6/7*100

Now taking the answers of all the values in decimal we will get the values as
33.33, 40, 42.84, 80, 83.35, 85.68

Now arranging the value in descending order we get as
85.68, 83.35, 80, 42.84, 40, 33.33

6/7, 5/6, 4/5, 3/7, 2/5, 1/3 right answer.

@All.

A B and C options start with 1/3.

This means they are in ascending order
only D starts with 6/7,
This is arranged in descending order.
So, D is the answer.

First cross multiply each term with adjacent next term. So we get a number series as follows.

Eg. take option D.

6*6 = 36
7*5 = 35
5*5 = 25
6*4 = 24
4*7 = 28
5*3 = 15
2*3 = 6
1*5 = 5

From this series we clear that it is in descending order.