Hi

Mid.      Class.    Freq.   Cuml

point.    Group.               Freq

5           0-10        3          3

15         10-20      9         12

25          20-30     8         20

35         30-40       5         25

45        40-50       3          28

h= 15-5= 10

h/2 = 10/2=5

5+5 =10

5-5=0

Therefore class group for 5 midpoint is 0-10

Cumulative freq calculated as

Freq 3 is 3

Freq 9 is 3+9 =12

Freq 8 is 12+8=20...

Hence forth N = 28

N/2= 14

Cumulative freq closest to 14 is 12 hence class group is 10-20 and f=9

Median = l+(N/2-F)/f * h

l =10 (lower limit of 10-20)

F= 3 ( cumulative freq that comes before 12)

f=9

h=10( difference between 10-20)

Median= 10+(14-3/9)*10

=22.22approx

Get back to me again if you find any error here.