How fast were they traveling?

Question

At 3:00 pm they are 75 miles away; they checked again at 4:30pm and were 15 miles away. 

 

a) on average, how fast were they traveling?

 

b) write an equation that gives the distance from the original place (x) hours after 3:00pm. 

Answer 1

As Mark said, they travelled

60 miles in 1.5 hours giving a rate

of 60/1.5 = 40 mph

 

They are 75 miles away at 3pm and

approaching at 40 mph so the

distance away at t hours after 3 pm is

 

d = 75 - 40t

check: at 1.5 hrs they should be 15 miles away d = 75 - 40(1.5) = 75 - 60 = 15

Answer 2

In 1.5 hours (4:30 - 3:00) they traveled 60 miles (75 - 15)

60 mi / 1.5 hr

40 mi / 1 hr

d = 40t