Question

find the mean of 25number if the mean of 15 of them is 18 and the mean of the remaining number is 13

Answer 1

mean of fifteen number =sum of fifteen number /15=18 so sum of fifteen number =270 and sum of left number =sum of 10 number /10=13 then it's sum=130 then mean = sum of whole obtained number /25=270+130/25=400/25=16