Aptitude - Percentage - Discussion

Discussion Forum : Percentage - General Questions (Q.No. 8)
8.
Two numbers A and B are such that the sum of 5% of A and 4% of B is two-third of the sum of 6% of A and 8% of B. Find the ratio of A : B.
2 : 3
1 : 1
3 : 4
4 : 3
Answer: Option
Explanation:

5% of A + 4% of B = 2  (6% of A + 8% of B)
3

5  A + 4  B = 2 6  A + 8  B
100 100 3 100 100

1  A + 1  B = 1  A + 4  B
20 25 25 75

1 - 1  A =  4 - 1  B
20 25 75 25

1  A = 1  B
100 75

A = 100 = 4 .
B 75 3

Required ratio = 4 : 3

Video Explanation: YouTube Video

Discussion:
52 comments Page 4 of 6.

Kapil Beniwal said:   1 decade ago
Yeah thank you it looks simple but ratio a:b is diff than b:a. We generally think and solve b:a.

Romita said:   1 decade ago
4/75-1/25 is not equal to 1/75 then hw a/b is equal to 4/3

Priya said:   1 decade ago
@Romita

Take LCM for 4/75-1/25.

Radhika said:   1 decade ago
Thanks Nitish. It is so simple now.

Dhiraj chaurasia said:   1 decade ago
Thanks nitish ilike your sugession.

Allana said:   1 decade ago
@Nitish

your 3rd step '3(5A + 4B) = 2(6A + 8B)' after solving this we get answer as 'C' which is 3:4...

Here is my explanation from your step 3...

3(5A + 6A) = 2(4B + 8B)
3(5A + 6A) = 3x5A = 15A and 3x6A = 18A Total = 33A i:e A = 4(Approx)
2(4B + 8B) = 2x4B = 8B and 2x8B = 16B Total = 24B i:e B = 3

Taking A/B as 33/24 we get 4/3.

Ravi said:   1 decade ago
@Allana.

3(5A + 4B) = 2(6A + 8B).

=> 15A+12B=12A+18B.

=> 15A-12A=16B-12B.

=> 3A=4B.

=> A/B=4/3.

Breejesh said:   1 decade ago
@Nitiesh and @Allana.

I don't understand how 3a=4b that becomes a/b=4/3.

To me 3 is with a and 4 is with b so should not be it as 3:4.

Why answer is 4:3.

Vinod Anand said:   1 decade ago
According to Question is :

5xA/100 + 4xB/100 = 2/3(6xA/100 + 8xB/100).

5A+4B = 2/3(6A+8B).

15A + 12B = 12A + 16 B.

3A = 4 B.

A:B = 4:3 , Option (D).

PARUL said:   1 decade ago
3(5A+4B) = 2(6A+8B).
15A-12A = 16B-12B.
3A = 4B.
A:B = 4:3.


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