preeti taught some children of slum areas for certain days. Then she organized a test for them in which she awarded one mark for each correct answer and deducted 1/2 mark for each wrong answer. A child did 40 questions and got 25 marks how many questions did she answer correctly?
Answers
Answer:
30
Step-by-step explanation:
Let no. of right questions attempted by student be = x
Therefore, no. of wrong questions attempted = 40-x
Marks awarded for each right answer = 1
Marks awarded for x right answers
= 1(x)= x
Marks deducted for each wrong answer = 1/2
Marks deducted for 40-x wrong answers
= 1/2 × (40-x)
Total marks obtained
= Marks awarded - Marks deducted
Therefore,
25 = (x) - 1/2(40-x)
On solving we get
x = 30
Therefore no. of correct answers given by student = 30
and that of wrong ones = 40-30 =10
Answer:
she answered 30 questions correctly
Step-by-step explanation:
let she answered 'x' correct and 'y' wrong questions respectively
given total questions is 40..i.e,
x+y=40-------------------(1)
given, 1mark for correct question and 1/2mark deducted for wrong one..and he finally got 25 marks
x-(1/2)y=25
2x-y=50-------------------(2)
solving (1)&(2)
x+y=40
2x-y=50
----------------
3x =90
x=30
put 'x' value in eq(1)
30+y=40
y=10
hence she answered 30 questions correctly and 10 questions wrong