Q. 124.6( 7 Votes )

# Find the missing

Answer : It is given that, mean = 50 = 50 = 50

3480 + 30f1 + 70f2 = 50 (120)

30f1 + 70f2 = 6000 – 3480

10 (3f1 + 7f2) = 10 (252)

3f1 + 7f2 = 252 (i) [Dividing by 10]

And N = 120

17 + f1 + 32 + f2 + 19 = 120

68 + f1 + f2 = 120

f1 + f2 = 52

Multiplying by ‘3’ on both sides, we get

3f1 + 3f2 = 156 (ii)

Subtracting (ii) from (i), we get

3f1 + 7f2 – 3f1 – 3f2 = 252 – 156

4f2 = 96

f2 = = 24

Put value of f2 in (i), we get

3f1 + 7 * 24 = 252

3f1 = 252 – 168

3f1 = 84

f1 = = 28

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Conservation of Energy41 mins  Pair of Angles29 mins  Division of Polynomials46 mins  Important Articles of Indian Constitution50 mins  Equations of Motion41 mins  Work and Types of Work done40 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses RELATED QUESTIONS :

Find the missing RD Sharma - Mathematics

Find the median oRD Sharma - Mathematics