100-0.0124=99.9876
10%=1/10
1/10P=P(0.999876)^t
divide both sides by P
1/10=0.999876^t
take ln of both sides
ln(1/10)=t (ln(0.999876))
divide both sides by (ln(0.999876))
ln(1/10)/(ln(0.999876))=t
use calculator
18568.08=t
about 18568 years
The width is 8 because 4x8=32
Answer: 11, 45, 45, 54, 520
The proportion of buses traveling more than 900 miles would be 0.0485; multiply this by the total number of buses and you will have your answer.
We find the z-score associated with 900 miles:
z = (X - μ)/σ = (900-830.11)/42.19 = 1.66
Using a z-table (http://www.z-table.com) we see that the area under the curve to the left of this, less than this, is 0.9515. This means that the area under the curve to the right of this, greater than this, would be 1-0.9515 = 0.0485.
