If speed varies inversely as the time it takes to drive and Kris takes 5 hours driving at 55 mph, what speed will Martin need to drive if he wants to take 5 hours?
O 50 mph
52.4 mph
O 60.5 mph
O 51.5 mph

55mph

None of the option is correct

Step-by-step explanation:

Let v be the speed and t as the time taken. If speed varies inversely as the time it takes to drive, then v ∝ 1/t.

v = k/t where k is the constant of proportionality.

IF it takes Kris 5 hours when driving at 55 mph, then v = 55mph when t = 5 hours.

Substituting this values into the formula above;

55 = k/5

k = 55*5

k = 275mp/hr²

To calculate the speed it will Martin to  drive for 5 hours, we will substitute k = 275 and t = 5 into the original equation v = k/t

v = 275/5

v = 55 mph

Hence, martin will also need to drive at 55mph to take 5 hours