if the median of the following frequency distribution is 24. find the missing frequency x :
Age Number of persons
0 - 10 5
10 - 20 25
20 - 30 x
30 - 40 18
40 - 50 7
Le t us assume that the median lies in the range 10-20
⇒ 
⇒ x = 25
As x has an acceptable value our assumption is correct and x =25