Step-by-step explanation:
1.5 : 2.5
= 1.5/2.5
15/25
3/5
the ratio is 3 : 5
to get the equation of any straight line, we simply need two points off of it, let's use those two points in the picture below.

keeping in mind that for the point-slope form, either point will do, in this case we used the second one, but the first one would have worked just the same.
Answer:
The probability that it would take more than four hours to construct a soapbox derby car = 0.1587 or 15.87
Step-by-step explanation:
Given -
Mean
= 3 hours
Standard deviation
= 1 hours
Let X be the no of hours to construct a soapbox derby car
the probability that it would take more than four hours to construct a soapbox derby car =
= 
=
Put 
= 1 -
= 1 - .8413 Using z table
= 0.1587