if the mean of the following data is 15 then find the value of p
X 5 10 15 20 25
F 6 4 5 p 7
x | f | fx |
5 | 6 | 30 |
10 | 4 | 40 |
15 | 5 | 75 |
20 | p | 20p |
25 | 7 | 175 |
total | ∑f=22+p | ∑fx=320+20p |
mean =∑fx/∑f
15=(320+20p)/(22+p) (since mean =15)
15(22+p)=320+20p
=> 330+15p=320+20p
=> 330-320=20p-15p
=> 10=5p
=> 5p=10
=> p=10/5 =2
=> p=2