Aptitude - Percentage - Discussion

Discussion Forum : Percentage - General Questions (Q.No. 2)
2.
Two students appeared at an examination. One of them secured 9 marks more than the other and his marks was 56% of the sum of their marks. The marks obtained by them are:
39, 30
41, 32
42, 33
43, 34
Answer: Option
Explanation:

Let their marks be (x + 9) and x.

Then, x + 9 = 56 (x + 9 + x)
100

25(x + 9) = 14(2x + 9)

3x = 99

x = 33

So, their marks are 42 and 33.

Discussion:
170 comments Page 5 of 17.

Rahul said:   1 decade ago
This is how I understood :

x = y+9.
x = 0.56(x+y).

x-y = 9.
x-0.56x-0.56y = 0.

0.44x-0.56y = 0.
x = (0.56/0.44)y.
x = (56/44)y.

(56/44)y - (44/44)y = 9.
(12/44)y = 9.
y = 9*44/12.
y = 3/4*44=3*11=33.
y = 33.

x = 33+9.
x = 42.

Anu said:   1 decade ago
=> 25(x + 9) = 14(2x + 9).
=> 3x = 99.

How it became this?

Suseela said:   1 decade ago
Please, don't confuse with these calculations, my advice is to go by options because, we have two exam marks.

And in question they have asked about the 56% of sum of two exam marks. So go by this way.

Check options:

1. 56/100*69 = 38.
2. 56/100*73 = 40.88.
3. 56/100*75 = 42.
4. 56/100*77 = 43.12.

So the option 3 answer matches with the option 3 in the question. The correct answer is option 3. i.e.. 42, 33.

Suren said:   1 decade ago
Its very simple.

What is the % difference 12% mark difference 9 if 12% = 9; 56%=?

56*9/12 = 42 which is highest mark.

So 42-9 = 33.

Answer is 42, 33.
(1)

Sneha said:   1 decade ago
He got 9 marks.

Kavi said:   1 decade ago
How come x+x+9?

Debasis Biswas said:   1 decade ago
Correct answer is 42, 33.

Chandan pandit said:   10 years ago
Please clear this.

Tukuna Behera said:   10 years ago
Dear @Chandan it is very simple,

Two students total mark in percentage is 56% that mention in the question.

If we discuss this line the result is x+y = 56%.

But the question says one of them secured 9 marks than other.

So we assume one student is (x+9) and other is x.

Here x+9 means x+9 is secured 9 marks extra than x.

Now if we try to find out the value of x from x+9. If we find out the x output then we must find out both students mark.

x+9 = 56(x+9+x)/100 [here we write 56(x+9+x) means both students percentage is 56%].

x+9 = 14(x+9+x)/25.
25(x+9) = 14(2x+9).

3x = 99 [25x+225 = 28x+126 => 28x-25x = 225-126 =>3x = 99].

x = 33[x = 99/3 => 33].

Now the original output is:

Two students are: x, (x+9).

1st student's mark is: x = 33.

2nd student is secured 9 marks than 1st student => (x+9) = 33+9 = 42.

Output option is C: 42, 33.
(1)

2ku said:   10 years ago
Dear @Kavi,

Here we assume that two students mark, one is secured than other in 9 marks.

So let 1st student is x.

2nd student is x+9 [2nd student is secured 9 marks than 1st].


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