Question

Find the missing item, if mean of the following series is 50. (3 marks)
MARKS 30 35 40 ? 50 75 NO. OF 1 2 3 4 6 4 STUDENTS

Answer 1

50=30+35+40+50+75+x/6

50=230+x/6

50×6=230+x

300=230+x

x+230=300

x=300-230

x=70

Answer 2

Answer:

Given : total no . of  students =  6

       marks = 30, 35, 40, x,50 75

        mean = 50

Mean =  sum of marks obtained  / total no. of students

mean = $\frac{30 + 35 + 40 + x + 50 + 75}{6}$

     $50$   =  $\frac{230 + x}{6}}$

    $300$   =  $230 - x$

        $x = 300 - 230\\x = 70$

Therefore , missing term is 70

 

Explanation: