Directions: Q. 6 to 10 | ||
A test consists of 'True' or 'False' questions. One mark is awarded for every correct answer while \[\frac{1}{4}\] mark is deducted for every wrong answer. | ||
A student knew answers to some of the questions. Rest of the questions he attempted by guessing. He answered 120 questions and got 90 marks. | ||
Type Question | Marks given for correct answer | Marks deducted for wrong answer |
True/False | 1 | 0.25 |
A) 96
B) 92
C) 90
D) None of these
Correct Answer: A
Solution :
Let the number of questions whose answer is known to the student be x and questions attempted by guessing be y. |
Then, x+y=120 ...(i) |
and \[x-\frac{1}{4}y=90\] |
\[\Rightarrow \,\,\,\,\,\,4x-y=360\] … (ii) |
On adding Eqs. (i) and (ii), we get |
\[5x=480\] |
\[\Rightarrow x=\frac{480}{5}=96\] |
Put x = 96 in Eq. (i), we get |
\[96+y=120\Rightarrow y=120-96=24\] |
He answered 96 questions correctly. |
You need to login to perform this action.
You will be redirected in
3 sec