I solved it and got 388.21
This equation can be set up letting x be the hourly rate:40x+1.5x(52-40)=638 [40 times the rate, plus 1.5 times the rate for the hours over 40 equals the pay]40x+78x-60x=63858x=638x=11 hourly rate is $11/hr
For this case we have to take into account the following conversions:

Let's first transform the expression to miles per seconds squared:

Then, we transform the result to miles per minute squared.
We have then:
Answer:
the rate in miles/min^2 is: