The arithmetic mean of the following data is 25, find the value of k.


xi:



5



15



25



35



45



yi:



3



k



3



6



2



[CBSE 2001]


X



y



yx



5



3



15



15



K



15k



25



3



75



35



6



210



45



2



90




N = 14 + k



∑yx = 15k + 390



Given,


Mean = 25


= 25


= 25


15k + 390 = 25 (14 + k)


15k + 390 = 350 + 25k


40 = 10k


k = 4


14