Question

10. A test contains 10 true/false questions. A correct
answer is awarded 2 marks, a wrong answer -1 and
a question not answered is awarded 0. A student
attempts 7 questions and gets 8 marks. How many
questions did the student answer correctly?​

Answer 1

Answer:

ok ill answer the question and ill try my best to answer all the questions but read completely for detailed perfect explanation

Step-by-step explanation:

Now he attempted 7 questions,so there are some wrong answers and some are correct. so let the no of correct answers be x and wrong answers be y so for each correct answer he gets 2 marks now for every wrong answer -1 so incase of marks we can observe he got negative marks because if he attempted all questions correct then he would get 14 marks but that did not happen. then 2 × x gives marks he got for correct answers and -y ×1 gives total negative marks so 2x -y =8 then on adding first and second equation 2x-y+x+y=8+7.then we get 3x =15 and x =no of correct answer=5!