Data set A and data set B each contain 5 numbers. If the mean of data set A is equal to the mean of data set B, what is the value of x ?
77
85
86
95
Choice C is correct. The mean of a data set is found by dividing the sum of the values in the data set by the number of values in the data set. Therefore, the mean of data set A is , which simplifies to 74. The mean of data set B is represented by the equation
, or
. It’s given that the mean of data set A is equal to the mean of data set B. Therefore, the equation
can be used to solve for x. Multiplying both sides of this equation by 5 yields
. Subtracting 284 from both sides of this equation yields
.
Choices A, B, and D are incorrect and may result from calculation errors.