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

Answer :- 28

$\bf\huge\underline{\underline{ Given :- }}$

• there are 100 questions

• +3 marks for correct answer

• -1 mark for wrong answer

• student attempted 90 questions and scored 158 marks

$\bf\huge\underline{\underline{ To \: Find:- }}$

• no. of wrong answers

$\bf\huge\underline{\underline{ Answer :- }}$

• let the number of right answers be" a"

• number of wrong answers be " b "

3a - b = 158 ------------(1)

• the total number of right and wrong is 90

a + b = 90 -------------(2)

solving the equation ,

• 4a = 248

• $\bf\red{a = 62}$

• b = 90 - 62

• $\bf\red{b = 28}$

$\rule{10cm}{0.05cm}$

he got 28 questions wrong