Question

Joan and her brother Justin left a hotel at the same time, driving in opposite directions at constant rates. After traveling for 4 hours, they were 480 miles apart. If Justin drove 10 miles per hour faster than Joan, how fast did Joan drive?

Answer 1

Answer:

55mph - got it right :p

Step-by-step explanation:

make other person brainliest please

Answer 2

Answer:

Joan drive with a speed of 55 miles per hour.

Step-by-step explanation:

Given:- Travelling time (t) = 4 hours.

Travelled distance (d) = 480 miles.

Speed of Justin is 10 miles per hour faster than Joan.

To find:- Speed of Joan = ?

Solution:-

Let speed of Joan be x,

therefore speed of Justin = x+10          ---------------(from given)

Now, Total speed of Joan and Justin = x+x+10

Total speed of Joan and Justin = 2x+10 ------------(1)

Now formula for speed is,

Speed = $\frac{distance}{time}$

$2x+10=\frac{480}{4}$                        -------------(from 1 and given)

$2x+10=120$

$2x=120-10$

$2x=110$

$\therefore x=\frac{110}{2}$

$\therefore x= 55$

as x is the speed of Joan,

Therefore Joan drive with a speed of 55 miles per hour.