Average Ques 5
Question-
Average score of a class of 50 students, in an exam is 34. Average score of the students who have passed is 52 and the average score of students who have failed is 16 . How many students have failed in the exam?
(1) 25
(2) 20
(3) 15
(4) 18
(5) 30
(IBPS RRBs Officer Scale-I & II CWE 13.09.2015)
Show Answer
Correct Answer: (1)
Solution: (1)
Number of failures in the exam $=x$ (let)
$\therefore$ Number of successful students $=50-x$
According to the question,
$52(50-x)+16 x=50 \times 34$
$\Rightarrow 2600-52 x+16 x=1700$
$\Rightarrow 2600-36 x=1700$
$\Rightarrow 36 x=2600-1700=900$
$\Rightarrow x=\frac{900}{36}=25$
Aliter :
In this type of questions we can use alligation method.
No. of failed students $=\frac{1}{1+1} \times 50=\frac{50}{2}=25$
BETA
