Aplane flies round-trip to philadelphia. if flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour. if the total trip takes 6.5 hours, how many miles does the plane fly round-trip?

560 miles

800.8 miles

1,300 miles

1,601.6 miles

To solve the problem we will use this equation where,

d will be distance.
x is the speed of the plane without tailwind. 
y is the speed of the wind affecting the plane.
Going to Philadelphia the speed of the plane affected by wind will be x-y=220 miles/hr
Coming back with a tailwind, the speed of the plane will be x+y= 280 miles/hr.
since time = distance / speed, t1 =d/220 and t2 = d/280
and since the total time traveled is 6.5hrs
d/220 + d/ 280 = 6.5hrs
d = 800.8 miles x 2 (back and forth trip) the answer is 1601.6 miles

If gravity is one third on mars then weight also one third on mars