Question

How will adding the value 200 affect the mean and median of the data set 10, 15, 17, 17, 19, 20?

Answer 1

The median of the original set is 17 (the two middle numbers are both 17) and the median of the new set is also 17. I could stop here, because only one option says that the median stays the same, but I'll show how the mean increases. The mean of the original set is (10+15+17+17+19+20)/6, which is 98/6, which is 16 and 1/3. The mean of the new set is (10+15+17+17+19+20+200)/7, which is 298/7, which is  42 and 4/7. Therefore, the mean increases and the median stays the same, meaning answer A is correct.