Question

Suppose you have a data set that includes the values 2030 and 50 if you add a fourth value to this data set in after doing that the mean of the data set is 50 what was the value that you added?

A. -10
B. 40
C. 50
D. 100

Answer 1

D

Explanation:

Without doing any math, you can deduce that in a data set with the values 20, 30, and 50, the only possible number you could add that could bring the mean (average) to 50 would be D or 100. But this method will not always work so instead I'll show how to do it mathematically:

(20 + 30 + 50 + x)/4 = 50

20 + 30 + 50 + x = 200

100 + x = 200

x = 100