# The mean of 9 observations is 16. One more observation is included and the new mean becomes 17. The 10th observation is :

The mean of 9 observations is 16. One more observation is included and the new mean becomes 17. The 10th observation is :
[A]9
[B]16
[C]26
[D]30

26
Mean of ten observations – Mean if nine observations = Tenth observation
= 10 $\times$ 17 – 16 $\times$ 9
= 170 – 144 = 26
Hence option [C] is correct answer.