Answer:
(-6,-4)
Step-by-step explanation:
Hope this helps! (:
Let

denote the number of minutes spent brushing his teeth, and let

be the mean and

the standard deviation for this distribution.

The z-score corresponding to this probability is approximately

, which means

Next, (note the sign change)

The corresponding z-score is approximately

, so you have

Solving the two equations for

and

, you'll find that the mean is approximately

and the standard deviation is approximately

.
180 = 3x + 5x + 2x +5
180 = 10x + 5
175 = 10x
x = 17.5
180 is how many degrees in a triangle
Answer:
chances are 10.5
Step-by-step explanation: