In a competitive examination, one mark is awarded for every correct answer while 1/4 mark is deducted for every wrong answer. A student aswered 100 questions and got 80 marks. How many questions did he answer?
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Answers
Correct Question :
In a competitive examination, one mark is awarded for every correct answer while 1/4 mark is deducted for every wrong answer. A student answered 100 questions and got 80 marks. How many questions did he answer correctly ?
Answer:
No. of questions answered correctly = 84
Step-by-step explanation:
Given,
- one mark is awarded for every correct answer while 1/4 mark is deducted for every wrong answer
- A student answered 100 questions and got 80 marks
To find,
- the questions answered by him correctly
Solution,
Let the number of questions answered correctly be "x"
and the number of questions answered incorrectly be "y"
Total number of questions answered = 100
x + y = 100 --[1]
- Marks awarded for every correct answer = 1
Marks awarded for "x" correct answers = 1 × x = x
- Marks deducted for every wrong answer = 1/4
Marks deducted for "y" wrong answers = y/4
The student scored 80 marks.
x - y/4 = 80
4x - y = 80 × 4
4x - y = 320 --[2]
Add both the equations,
x + y + 4x - y = 100 + 320
5x = 420
x = 420/5
x = 84
Therefore,
the number of questions answered by him correctly = 84