Aptitude - Ratio and Proportion - Discussion

Why is 57 on the side of 2 and 40 on the side of 3 is 2 greater than 3 in a 2:3 ratio?

Here is the best possible way I realised how they went from 6x to 3x.

If we follow the general standard:
Let the ratios be 2x and 3x.
Now we know that both get Rs. 4000, so it should look like this:

Ravi : (2x + 4,000)
Sami: (3x + 4,000)

Now they gave us the new ratio of what it would be after they got their added amount: 40 : 57.

By looking like this: (2x + 4,000) = 40 / (3x + 4,000) = 57 (Sorry for poor demonstration here)

By cross multiplying the values, it should look like this: 57(2x + 4,000) = 40(3x + 4,000)
We will then expand it out: 114x + 228,000 = 120x + 160,000
Then by simplifying it through this stage:
228,000 - 160,000 = 120x - 114x

The answer should look like this: 68,000 = 6x
It can also be written as: 6x = 68,000, it's still the same thing, just that 6x is on the other side for personal preference and ease of simplifying.

Now the problem is this instant go from 6x to 3x, but what is 6x? I don't know. My best possible answer is that it's nobodies amount and that you would rather want to find x, so that you could multiply is by 3 to get Sumit's salary:

Finding x (divide both sides by 6): 6x/6 = 68,000/6
x = 11333.333333333333333333333333333
Now multiply it by 3 -> 11333.333333333333333333333333333 * 3 = 34,000.

This is this only way I could rationally come to understand this jump from 6x to 3x and hopefully it has made sense to you.

Here are some questions I would like to respond to for some of the users:

@Tluanga Chhangte : The reason why you see it like that is because the actual way they should present the subtraction is like this:
(228,000 - 160,000 = 120x - 114x). The reason why x was on the left side on their sheet was possibly due to their minds having "x" on the left side and that is understandable as I do that myself sometimes.

The way this person did it: (114x-120x=228000-160000) would be quite miss guiding as if we refer to the expanded one from earlier:

(114x + 228,000 = 120x + 160,000), if you were to subtract, it would be: (114x - 120x = 160,000 - 228,000) which would still equal 6x = 68,000 as the two negatives would cancel eachother out when dividing to find "x". Hopefully, this has solved your confusion @Chhangte.

@Priyanka The solution to your problem should be pretty simple since we know what x is from my calculation. All that would need to be done is multiply x by 2 to get 2x:
(2 * 11333.333333333333333333333333333 = 22666.666666666666666666666666667 or Rs. 22,666.67 (2 d.p.)
Hopefully, this has solved your problem.


Hope it will helps to understand easily.

What is the solution for finding the Ravi's salary?

The Salaries of Yasmeen and Adnan are in the ratio 1 : 2. If the salary of each is increased by Rs. 3000, the new ratio becomes 40 : 57. What is Adnan's present salary? Please solve this.

Please tell me. How 114x -120x = 228000 - 160000 becomes 6x = 68000 instead of -6x = 68000?

I think, it should be 114x - 120x = -6x.

Hello friends,

Already this sum answer is given,
Let the original salaries of Ravi and Sumit be Rs. 2x and Rs. 3x respectively.
Then, 2x + 4000 = 40.
3x + 4000 = 57,
Till here you public know from where this come,
After that 6x = 68000, this is little bit question to us. From where this we got.

Here is the answer.

Across multiple,
57 (2x + 4000) =40 (3x + 4000).
2 * 3x = 6x, 57 - 40 = 17, 4000 is common.
6x = 17 * 4000.
6x = 68000. Here we solve sum doubt.

Going forward, we have to find Sumit salary.
6x = 68000 divide two as per the given ratio.
3x = 34000.

So here we got the value of 3x = 34000.

Sumit salary is 3x + 4000.
Therefore, 3x = 34000 + 4000.
Answer is 38000 Rs.

Please explain me very short answer.

Please explain where did 68000 come from?

Why every one is taking this new ratio as 40/57 there may be a multiple for this i.e 40y/57y, here y is the multiple number other then x, can any one explain me about this, while doing cross multiplication it is important I think.

@Shalini I agree.

The question "What is Sumit's salary?" should be more clear.

-Is it Sumit's "present" salary?

-Or is it Sumit's "new" salary?

At first, I thought the question was asking for Sumit's "current" salary. The answer should be Rs. 34, 000.

But the given answer is Rs. 38, 000. That is Sumit's "new" salary (34, 000+4, 000) ("If" he got the raise) not Sumit's "present" salary as written in the explanation.