A747 jet airplane traveled 600 miles in two and a half hours if it travels at the same speed how long will it take to travel 1500 more miles ? ?

There are a fews ways to solve this. I am going to use the distance equation 
d = rt.

d = distance = 600
r = speed =
t = time = hours = 2.5

Lets find the rate/speed by plugging in what we know.
d = rt
600 = r2.5
600 /2.5 = r2.5 / 2.5
240 = r
r = 240

Now we got the rate/speed we can solve our problem. It wants to kow how long it will take to travel 1500 more miles from the 600 miles that has already traveled

d = rt
d  = 1500 
r = 240
t =

1500 = 240t
1500 / 240 = 240t / 240
6.25 = t
t = 6.25.
It will take 6.25  or as fraction 6(1/4) hours more.