Let 
be the short, medium and long side, respectively. If we translate all the information into formulas, we get the following system:
Using the second equation, we can express the middle side in terms of the small one, and reduce the system to two equations in two unknowns:
And thus
But then again, using the first equation, the third becomes
So, the longest side is 12. Since the small is half the long, we have 
. Finally, the medium is three more of the small, so we have 
Speed = Distance / time
Distance = Speed x time
In t hours, first plane travels = 600 t miles
In t hours, the second plane travels =150 t miles
After t hours the distance between the two planes is:
(600t+150t)= 750t ( since both travel in opposite directions)
When the distance is 900 miles:
750t= 900
Solve for t:
t= 900/750
t= 1.2 hours
After 1.2 hours.
1.2 x 60 = 72 minutes = 60 +12 = 1 hour and 12 minutes
Since both leave at 10 pm:
10am + 1 hour and 12 minutes : 11:12 am
They will be 900 miles apart at 11:12 am
Each one traveled:
Plane 1:
Distance: Speed x time = 600 mph x 1.2 = 720 miles
Plane 2:
Distance = Speed x time = 150 mph x 1.2 = 180 miles
Answer: I think it’s the first one
Step-by-step explanation:
It says per hour and 15 bucks plus 5 bucks PERhour so you would have to be multiplying I did a question like this long ago hope you get it right
