"david left the park traveling 16 mph. then 3 hours later, corey left traveling the same direction at 28 mph. how long until corey catches up with david?

The answer to your question 4 hours

Step-by-step explanation:

Data

David = 16 mph

Corey = 28 mph

first time = 3 hours

time = ?

Formula

solve for distance

distance = v x time

Process

1.- Calculate the distance David travelled during 3 hours

    distance = 3 x 16 = 48 m

2.- Write equations for the distance travelled by David and Corey

   David = 16t + 48

   Corey = 28t

3.- Equal both equations

                16t + 48 = 28t

4.- Solve for t

                16t - 28t = - 48

                -12t = -48

                    t = -48/-12

5.- Result

                    t = 4 hours

it will take 7 hours until Corey catches up with David

Step-by-step explanation:

At the time David catches up with Corey, they would have travelled the same distance. Let x represent this distance.

Distance = speed × time

Let t represent the time that David takes to cover x miles. David left the park traveling 16 mph. Therefore,

x = 16 × t = 16t

Then 3 hours later, Corey left traveling the same direction at 28 mph. It means that total time spent by Corey in travelling x miles is t - 3.

Distance travelled by Corey in (t - 3) hours would be

28(t - 3)

Since the distance covered is the same, then

16t = 28t - 84

28- 16t = 84

12t = 84

t = 84/12

t = 7 hours