Answer:
40
Step-by-step explanation:
Answer:
x=7
Step-by-step explanation:
x+4=4x-17
4=3x-17
21=3x
x=7
The '68-95-99.7' rule says
-About 68% of values fall within one standard deviation of the mean.
-About 95% of the values fall within two standard deviations from the mean.
-Almost all of the values — about 99.7% — fall within three standard deviations from the mean.
Here 
Therefore, the probability

The required probability

Multiply the numerator and denominator by the whole number. you'll most likely get an improper fraction though.