SOLUTION: In a exam there are 50 question.each correct answer fetches 1 mark whereas for each wrong answer,1/3rd mark was deducted.a student attempted all question and got 10 marks find the

In a exam there are 50 question.each correct answer fetches 1 mark whereas for each wrong answer,1/3rd mark was deducted.a student attempted all question and got 10 marks find the no. of question be correctly answerd
Ans:
Let the number of correctly answered questions be x
Then the number of incorrectly answered questions = (50-x)
Marks scored for correct answers = x*1 = x
Marks scored for incorrect answers = (50 - x)*(-1/3) = (x - 50)/3
Total marks scored is given as 10
So,

Multiplying by 3 to get rid of the fraction,

Simplifying and adding like terms
 or 
So number of questions correctly answered = 20
No. of questions wrongly answered = 50 - 20 = 30
:)