ExoYT

let the speed be x 

time be in mins

 so we can form an equation

which is 216x= 225(x-30)

if we expand, we get

216x=225x-6750

so 9x=6750

x=6750/9

=750.

Since the speed is 750 miles per min,

distance= 750*216=162000 miles (per min)

so we have to divide by 60.

162000/60=2700 miles per hour

We can let a hot dog be H and a roll be R.

8H + 7R = $13.60

7H + 8R = $13.40

If we add the equations, 

we get

15H + 15R = $27

that means that 

H+R=$27/15

so the answer is 27/15.