Problema Solution
Pairs of markings a set distance apart ore made o highways so tht police can detect drivers exceeding the speed limit. Over ficed distance, the speed R varies inversley with the time T. in one particular pair of markings, R is 44 when T is 9 seconds. Fin the speed of a car that travels the given distance in 5 seconds.
Answer provided by our tutors
the speed R varies inversely with the time T means:
R = k/T, where k is constant
First we will find k using the fact that in one particular pair of markings, R is 44 when T is 9 seconds:
R = 44
T = 9 s
plug into R = k/T
44 = k/9
k/9 = 44 multiply by 9 on both sides
k = 44*9
k = 396
now we know the equation:
R = 396/T
for T = 5 second we have:
R = 396/5
R = 79.2
the speed of the car that travels the given distance in 5 seconds is 79.2.