Question

the mean of 10 numbers is 65 . out of which mean of first 9 is 50 .find the 10th number

Answer 1

Answer:

Mean  = sum of observations/no.of observations

so, mean of 9 nos = sum of 9 nos/ 9

50 = sum of 9 nos/9

sum of 9 nos =50*9 =450

let 10th no be x

mean of 10 nos = (sum of 9 nos +x)/10

65=450+x/10

650=450+x

x = 650-450 =200

10th no. is 200