20 POINTS! The time t required to drive a certain distance varies inversely with the speed r. If it takes 4 hours
to drive the distance at 50 miles per hour, how long will it take to drive the same distance at 40
miles per hour?

1.78 hours

Step-by-step explanation:

If t varies inversely with the speed, the formula for that is  t= \frac{k}{r} .  If t = 2 and r = 40, then we can solve for k, the constant of variation.  Multiply both sides by 40 to get  k = 80.  Now we need to find the value for t when r = 45.  Using the k value we just solved for, we will fill in the equation as  t= \frac{80}{45}   for a t value of about 1.78 hours

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step-by-step explanation: