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 15 of 17.

Ganesh said:   1 decade ago
very 1 stape is just to calculate total marks in each option,
suppose, I'm choosing 39 30 then total marks are 69 which is 100% if u calculate 56% of 69 i.e 56*69/100 you get 38.64 which is not in option. so leave it there.

if you're taking 42 33 then total marks are 75 which is 100% and 56% of 75 is 42 hence option C is correct.

though it is lengthy procedure, we can choose the option for calculation by little thinking before solving it.
(2)

SpT said:   1 decade ago
@Aniket.

Let total mark be x.

50% of x--> (50/100)*x = (1/2)x

Therefore (1/2)x-100 = P --(1). Here P is the pass mark.

70% of 1st candidate marks--> 70% of (1/2)x
(7/20)x.

Therefore (7/20)x+50 = P --(2).

Then equating (1) and (2) we get,
(1/2)x-100 = (7/20)x+50 ==> 3x = 3000.
x = 1000.

Then 50% of x
(50/100)*1000 = 500.

500-100 = 400;
400 is the Answer.

Aniket said:   1 decade ago
I need help on following question:

A candidate who gets 50% of total marks gets 100 marks more than the pass marks. Another candidate who gets 70% of the first candidates marks failed by 50 marks. How much percent a student needs to pass the exam?

Sri Ram said:   1 decade ago
Took 25 minutes to crack the stupid nut. The commonly confused place is (56%o of TOTAL marks so it is written as (x+9) +x where x is marks scored by one person and x+9 is marks scored by the later.

Aravind said:   1 decade ago
Why we put equate here between x+9 = 56/100* (x+9+x).

NJK said:   1 decade ago
Suraj and Radhika's answers are super. But Suraj answer is little confusing.

Fahad khan said:   1 decade ago
@Sarwat.

First assume that the number is x so.
Their 30% is x*30/100 which is equal to 180 i.e. x*30/100 = 180.

So x=60 again 3 times of that number is 180 and their 15% is equal to 180*15/100 = 27 that's the answer.

Suhas said:   1 decade ago
Instead of calculating using variables, use options to find the answer.

42 is 56% of 75, hence 3 is the answer.

Sarwat said:   1 decade ago
30 percent of a number is 180. What is 15 percent of 3 times of the same number?

Please help me in this question.

BM NAIDU said:   1 decade ago
Why we equqte x+9&(56/100(x+9+x)?

Can u please explain in simple way.


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