Question

. In an examination, a student is awarded 2 marks for correctly answering a question and

penalized 1 mark for wrongly answering a question. If in all he attempts 210 questions and obtains

150 marks then find the number of questions correctly answered by him?​

Answer 1

Answer:

let no of correct ans = X

and no of incorrect ans = Y

According to question

2X - 1Y = 150

X + Y = 210

by solving this by substitution we get

no of correct answer 120

I hope this will help