Question

answer this question attached
step by step explanation needed​

Answer 1

$\fbox\blue{A}\fbox\pink{N}\fbox\red{S}\fbox\green{W}\fbox\orange{E}\fbox\purple{R}$

Mean = 50

C.I. :- 0-20 , 20-40 , 40-60 , 60-80 , 80-100

Frequency (fi) :- 7 , 28 , 32 , f , 19 = 86 + f

$\large{\boxed{\red{Class\:mark\:=\: \frac{Upper\:limit=Lower\:limit}{2}}}}$

C.M. (xi) :- 10 , 30 ,50 , 70 , 90

(fixi) :- 70 , 840 , 1600 , 70f , 1710 = 4220 + 70f

$mean = \frac{ \sigma \: fixi}{fi}$

$= > 50 = \frac{4220 + 70f}{86 + f}$

$= > 50(86 + f) = 4220 + 70f$

$= > 4300 + 50f = 4220 + 70f$

$= > 4300 - 4220 = 70f - 50f$

$= > 80 = 20f$

$= > f = \frac{80}{20}$

$= > \huge \: \ \color{cyan} \: f = 4$