Amy V. answered 11/11/19
Experienced ACT/SAT and Math Tutor
For this question, we need to use the z-score formula to work backwards and solve for the mean.
The z-score formula is:
z = (X - mean) / standard deviation
In this case, we know that z = 3, X = 148, and standard deviation = 8, so we just plug those values in.
3 = (148 - mean) / 8
Start by multiplying both sides by 8 to cancel out the denominator. That gives you:
24 = 148 - mean
Subtract 148 from both sides to get:
-124 = -mean
So, the mean is 124.