REVIEW RATIONAL FUNCTIONS

Question

Kieley and Courtney are going to do a flash mob. Kieley lives 1 miles away and Courtney lives 5 miles away. What speed does Courtney need to travel if they leave at the same time given that Kieley walks and Courtney run 10 mph faster than Kieley?(They want to meet at the flash mob at the same time)

Answer 1

Kieley lives 1 mile a way, Courtney lives 5 miles away. Kiely walks and Courtney runs 10 mph faster than Kieley walks. The want to meet at the same time. When should they leave

distance = speed times time

d=st

time = distance divided by speed

t = d/s

t = 5/c = 1/k where c=Courtney's speed and k = Kieley's speed = c-10

5/c = 1/(c-10)

cross multiply

5c -50 = c

4c =50

c=50/4 = 12 1/2 mph

k = 2 1/2 mph

t = 5/(12 1/2) = 5/(25/2) = 5(2/25) = 2/5 of an hour = (2/5)(60) = 24 minutes

t =1/(2 1/2) = 1/(5/2) = 2/5 of an hour = 24 minutes

it takes Kieley 24 minutes to go 1 mile walking 2 1/2 mph

it takes Courtney 24 minutes to go 5 miles running at 12 1/2 mph

they can leave at the same time and arrive at the same time