Aptitude - Ratio and Proportion - Discussion

Discussion Forum : Ratio and Proportion - General Questions (Q.No. 14)
14.
Two number are in the ratio 3 : 5. If 9 is subtracted from each, the new numbers are in the ratio 12 : 23. The smaller number is:
27
33
49
55
Answer: Option
Explanation:

Let the numbers be 3x and 5x.

Then, 3x - 9 = 12
5x - 9 23

23(3x - 9) = 12(5x - 9)

9x = 99

x = 11.

The smaller number = (3 x 11) = 33.

Discussion:
27 comments Page 2 of 3.

Bharath said:   8 years ago
This question can be solved very easily.

Here the first ratio is a : b :: 3 : 5 that means "a" should be in multiples of 3 so the answer in the option must be either 33 or 27.

The next part is it is subtracted by 9 then the answer should satisfy ratio 12 : 23. So if 27 - 9 = 18 it is not multiple of 12 but 33 - 9 = 24.

24 is multiple of 12 so 24 is the answer.
(12)

Ajit said:   8 years ago
The two number should be X &Y and then their proportion is 3:5 then the sum will be 3x - 9/5y - 9 = 12/23.

23 (3x - 9) = 12 (5y - 9) => 69x - 207 = 60y - 108 = > 69x - 69y = 207 - 108 then what to do? Please tell me.

Rahul said:   9 years ago
Hi, I got this as answer, am I right?

(3x - 9)/(5x - 9) = 12/23.
3(x - 3)/(5x - 9) = 12/23.
(x - 3)/(5x - 9) = 4/23.
23 * (x - 3) = 4 * (5x - 9).
23x - 69 = 20x - 45.
3x = 24.
x = 8.

ADITYA MISHRA said:   9 years ago
3/5=2R (5-3=2 i.e. difference).

12/23=11R (23-12=11).

3/5*11 multiply by 2nd difference = 33/55.

12/23*2 multiply by 1st difference = 24/46.

9R = 9 i.e R = 1. So that smaller no 33.

Sathish said:   10 years ago
3x-9/5x-9=? How please explain?

Kanika said:   10 years ago
Why they multiplied 3 with x and 5 with y?

Gerald said:   1 decade ago
@Chandan.

From the question they gave new ratio as 12:23 so from the answer 3 * 11 =33. 33-9 =24. and 5 * 11 =55, 55-9=46, then it is in the ration of 24:46, therefore divide both by 2 you will get the new ratio of 12:23.

Vishnu said:   1 decade ago
@Sri.
In question asking only smaller number,
Let see 3:5 smaller number is 3, higher number is 5.

So that we take 3 *11 = 33.

Sri said:   1 decade ago
Shouldn't it be 55?

V.k said:   1 decade ago
@Chandan.

Because the no. is only 3x not the 3x-9.


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