Question

In an examination, there are 100 questions. Each correct answer fetches
3 marks and for each incorrect answer, 1 mark is deducted. No marks are
deducted for an unattempted question. A student attempts 90 questions and
scores 158 marks in total. How many questions did he get wrong?​

Answer 1

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Let number of correct questions be 'x' and let number of incorrect questions be 'y'.

$\large\bold\red{According \: to \: statement }$

Case 1:-

He attempt 90 questions out of 100.

=> x + y = 90..........(1)

Case 2 :-

3 marks and for each incorrect answer, 1 mark is deducted for each incorrect answer and he scored 158 marks in total.

=> 3x - y = 158.......(2)

Adding (1) & (2) equation

4x = 248

=> x = 62

Put x = 62 in equation (1), we get

62 + y = 90

=> y = 28

So, number of incorrect questions are 28.

$\red{\textsf{(✪MARK BRAINLIEST✿)}} \\ \huge\fcolorbox{aqua}{aqua}{\red{FolloW ME}}$

$\huge \fcolorbox{black}{yellow}{♛Hope it helps U♛}$