Evelyn's points per pinball game are normally distributed with a standard deviation of 18 points. If Evelyn scores 405 points, and the z-score of this value is −3, then what is her mean points in a game?

The mean point is 459

Step-by-step explanation:

We use the formula:

Evelyn's points per pinball game are normally distributed with a standard deviation of 18 points.

This means:

From the question, the standard deviation of 405 points is -3.

We substitute x=405, and z=-3 to get:

Multiply through by 18 to get:

Divide through by -1

207/8 is the right