Question

pair of markings , a set distance apart are made on highways so that police can detect drivers exceeding over the speed limit . over a fixed distance , the speed R varies inversely with time T . For one particular pair of markings , R is 50 mph when T is 7 seconds . find the speed of a car that travels the given distance in 5 seconds. please help

Answer 1

R varies inversely with time T means

R = k/T

for some constant k

Answer 2

R is 50 mph when T is 7 seconds

so plug in R = 50 and T = 7 and solve for k


R = k/T

50 = k/7

k = ???

Answer 3

350

Answer 4

so the equation is R = 350/T

Answer 5

"find the speed of a car that travels the given distance in 5 seconds."

now plug in T = 5 to find R

Answer 6

okay

Answer 7

what do you get?

Answer 8

355

Answer 9

oops mistake

Answer 10

R = 350/T

R = 350/5 ... replace T with 5

R = ??

Answer 11

70

Answer 12

yes

Answer 13

Thank you do to i'm not good on these problems

Answer 14

you're welcome