Over a fixed distance speed r varies inversely as time t. If the speed of a car is 30 mph when the time is 6 seconds what would the speed be of the car if the time was 4 seconds

1 answer

R1/R2 = T2/T1
V1/30 = 4/6
6R1 = 120
R1 = 20

or

R = kT, where k is a constant
given: R = 30 when T = 6
30 = 6k
k = 5

R = 5T
so when t=4
R = 5(4) = 20