1) In a test (+2) marks are given for every
correct answer and (-1) mark is given for
every incorrect answer. Saumya answered
all the questions and her score was 30
marks though she got 20 correct answers.
How many of her answers were incorrect?
Answers
Explanation:
since, she got 20 marks
She would have got 40 marks but she got 30 marks
Therefore, 40-30=10
For every wrong answer, -1 is given so number of incorrect answers= 10/1=10
GIVEN :-
- Number of marks alloted for every correct answer = +2
- Number of marks deducted for every incorrect answer = -1
- Number of marks scored by saumya = 30
- Number of questions saumya attempted correctly = 20
TO FIND :-
- The number of incorrect answers of saumya
SOLUTION :-
Let the number of questions saumya attempted incorrectly be x.
Number of questions saumya attempted correctly = 20
We are given that Number of marks alloted for every correct answer = +2
Then the marks alloted for 20 correct answers = 20(2) = 40
We are given that Number of marks deducted for every incorrect answer = -1
Then the marks deducted for "x" incorrect answers = (-1)(x) = -x
Total score of saumya = 30
Total marks scored = Number of marks alloted for correct answers + Number of marks deducted due to incorrect answers
→ 30 = 40 + (-x)
→ 30 - 40 = -x
→ -10 = -x
→ 10 = x
Hence , The number of incorrect answers of saumya are 10.