Average marks obtained by 180 students in an examination is 50 . If average marks of passed students

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The average marks obtained by $180$ students in an examination is $50 .$ If the average marks of passed students is $40 .$ Then what is the number of students who failed the examination ?

A

$90$

B

$135$

C

$100$

D

$45$

Solution

Failed Students be $x$

Passed Students be $180-x$

$\frac{(180-x) 80+x+40}{180}=50$

$14400-80 x+40 x=9000$

$40 x=5400$

$x=135$

Standard 13

Quantitative Aptitude

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