A candidate who gets 20% marks in an examination fails by 30 marks but another candidate who gets 32% gets 42 marks more than the passing marks. Then the percentage of pass marks is:

  1. 52%
  2. 50%
  3. 33%
  4. 25%
  • 4
    $\begingroup$ Note that you don't even have to do any calculations here; only one choice could possibly be right. $\endgroup$
    – pjs36
    Dec 28, 2016 at 17:17
  • 2
    $\begingroup$ You should explain what you don't get and explain what you have tried. This is insulting. $\endgroup$
    – The Count
    Dec 28, 2016 at 17:19
  • 1
    $\begingroup$ Haha, nice observation @pjs36. Anyways Shubham, if you wanna solve it nonetheless, it is a simple case of a system of two linear equations with two variables, passing marks and total marks. $\endgroup$ Dec 28, 2016 at 17:21
  • 9
    $\begingroup$ Thank you for copy-pasting your homework assignment into our service. Please stand by while our neural-network algorithm is auto-generating an answer to your question. One of our representatives will be with you shortly. On the meanwhile, please prepare your 16-digit credit card number, including your full name, expiration date and those 3 digits on the back of the card which for some reason are not on the front with the rest of them. Since this is a social-network web service, the cost will be 1 bitcoin per user. Thanks again for choosing to work with us. $\endgroup$ Dec 28, 2016 at 17:56
  • 4
    $\begingroup$ Sorry people. I think I have ended up at the wrong place. I was simply looking for a site where any question can be discussed without considering the asker's ability and capability. This place is good, but, not for what I am looking for. Anyways, I got an explanation and an insight view into my question. And, I was not copy pasting my homework or something. I was simply looking for someone, may be at the wrong place, who could have simply explained this to me without any extra comments. Wrong Place Wrong Time $\endgroup$ Dec 28, 2016 at 19:09

2 Answers 2


If you fail at 20% and pass at 32% the percentage at which you pass is between these. Only one option satisfies this.

Otherwise solve the system:

$$ 0.2x = y - 30 \\ 0.32x = y+42 $$

and you will know everything about your problem.

And show your work next time, this is not a homework service.

  • $\begingroup$ I gracefully accept your explanation. $\endgroup$ Dec 28, 2016 at 18:57
  • $\begingroup$ You showed me a simple way to look into such questions. I guess, I wont be solving them as equations when I encounter them again. Sir, thanks for your explanation. $\endgroup$ Dec 28, 2016 at 19:00
  • $\begingroup$ And, sir, don't mind me but I guess I have not asked for any kind of home-work service. I asked for an insight view and I am happy to have received that from your side. $\endgroup$ Dec 28, 2016 at 19:02
  • $\begingroup$ I'm sorry if I offended you, you must understand that a very high percentage of these kinds of questions are people posting homework problems, and in general, questions (even easier ones) are welcome if you show your own attempt. Glad I could help. $\endgroup$
    – JuliusL33t
    Dec 28, 2016 at 22:14
  • 1
    $\begingroup$ I get it sir. I guess, from next time onwards I will be clearly mentioning where I got stuck and I will show my approach too instead of simply asking it. $\endgroup$ Dec 29, 2016 at 8:20

Passing marks = 20% of x + 30 ....(1)

As he needs 30 more marks wo added.

Passing marks = 32% of x - 42 .....(2)

As he has 42 more marks then passing so subtracted.

From (1) and (2)

20% of x + 30 = 32% of x - 42

32% of x - 20% of x = 30 + 42

12% of x = 72

x = $\frac{72 * 100}{12}$

x = 600

So total marks 600.

From equation (1)

Passing marks = 20% of x + 30

= $\frac{20}{100}$ * 600 + 30 = 120 + 30 = 150

Passing percentage = $\frac{150}{600} * 100$ = 25%

  • $\begingroup$ good explanation. Thanx $\endgroup$ Dec 29, 2016 at 12:27

Not the answer you're looking for? Browse other questions tagged .