3 marks are awarded for each answer and 1 mark deducted for each wrong answer.a boy attempted 30 questions and scored 50 %. How many questions did he get wrong ?
It is not clear to me what 50 percent. The max score is 90, fifty precent is 45, which wont work out. I think your teacher did not mean to put the percent mark, but rather meant a score of 50.
(30-W)3-W=50
4W=40
wrong W=10 Correct=20
max, mark is 90,50 % is 45,he got 50 %,he got 45,if 3=1 que,45=15que,he got 15 que,there are 30ques,so 30-15=15,ans=15Q
To find out how many questions the boy got wrong, we first need to determine the total number of marks he received.
Let's assume the total number of questions attempted by the boy is x.
According to the given conditions, the boy scored 50%, which means he obtained half of the total marks possible.
Since each correct answer is awarded 3 marks, the total marks the boy could have obtained would be 3 times the total number of questions attempted. So, the total marks possible can be calculated as 3x.
Now, since the boy scored 50%, his actual score can be found by taking half of the total marks possible.
Actual Score = (50/100) * Total Marks Possible
= (50/100) * 3x
= (3/2) * x
The actual score the boy received is 50% of the total marks possible, which is equal to the actual score he obtained, considering the correct answers.
So, we have the equation:
(3/2) * x = Actual Score
Now, we can solve for x by substituting the given actual score, which we know is 50% of the total marks possible.
(3/2) * x = (3/2) * 30
x = 30
Therefore, the boy attempted 30 questions.
Now, to find the number of questions he got wrong, we can subtract the number of correct answers from the total questions attempted. Since each question has either a right or wrong answer, the number of questions he got wrong would be:
Number of wrong questions = Total questions attempted - Number of correct questions
= 30 - (Actual Score / 3)
= 30 - (30 / 3)
= 30 - 10
= 20
Hence, the boy got 20 questions wrong.