You can isolate r to one side of the equation by dividing by adding three, dividing by s, multiplying by a and you get:
r=a(3+k)/s
Multiply all the numbers of options together, so 5x3x4 to get 60 possible outfits.
(41 miles)/(2.3 hours) = 17.83 miles per hour.
Half an hour= two quarters of an hour
