Question

the mean of 8 number is 25. if ine more number is include, the mean of new set of number become 26. find the new number.

Answer 1

Given, Mean of 8 numbers is 25.

Then sum of those 8 numbers be 25*8 = 200

Also given the some more nine numbers gets added to the series, and new mean becomes 26.

then some of all (8+9) numbers in series becomes, 26*(8+9) = 26*17 =442

IF they have asked the SUM of the newly added nine numbers, then:  

442-200 = 242 is the answer