Question

if the average of 17 results is 60, if the average of first 9 is 57 and last nine is 65 what will be the value of ninth result

Answer 1

9th result=(57*9)+(65*9)-(60*17)=78

Answer 2

Solution:
 If the average of 17 results is 60, if the average of first 9 is 57 and last nine is 65,so the ninth result would be,

Let x be the ninth result.

x=(57*9)+(65*9)-(60*17)
x=(513+585)-1020
x=78

Therefore, the ninth result is 78.