solve the problem?
Answers
Step-by-step explanation:
Let the number of right answers be ‘a’ and number of wrong answers be ‘b’
Given, Yash scored 40 marks in a test, getting 3 marks for each right answer and losing 1 mark for each wrong answer.
Deducted marks are represented by "–" sign.
⇒ 3a – b = 40 ……(1)
Had 4 marks been awarded for each correct answer and 2 marks been deducted for each incorrect answer, then Yash would have scored 50 marks
⇒ 4a – 2b = 50 ……(2)
Multiplying eq1 by 2 and subtracting eq2 from it
⇒ 4a – 2b – 2(3a – b ) = 50 – 2 (40)
⇒ 4a – 2b – 6a +2b = 50 – 80
⇒ 4a – 6a = 50 – 80
⇒ 6a – 4a = 80 – 50
⇒ 2a = 30
⇒ a = 15
Put the value of a in eq. 1 to get,
3(15)–b=40
⇒ 45 – b = 40
⇒ –b=40–45
⇒ –b=–5
⇒ b=5
Total number of questions in the test = right answers + wrong answers
= 15 + 5
= 20