Use this website: https://www.angio.net/personal/climb/speed.html
Use this formula...
(-4 + 8) / 2 , (8 + (-4)) / 2
From there you get...
4 / 2 , 4 / 2
Simplify and you get
(2 , 2)
Answer:

Step-by-step explanation:
we have

<em>Find the amount of money that each girl spent</em>
For t= 2 hours



<em>Find the amount of money that they spend together</em>
Multiply by 2 the amount of money that each girl spent

672 is the answer to this question