<PRE><B>Question 758088</B>
The cruising speed of an airlines is 150 miles per hour (relative to
 the ground).
 you wish to hire the plane for 3 hour sightseeing trip.
 You instruct the pilot to fly north as far as he can and still return
 to the airport at the end of the allotted time.
 how far north should the pilot fly if the wind is blowing from
 the north at 30 miles per hour.
:
Let d = one way distance to point of return
we know
150 - 30 = 120 mph, ground speed going north
and
150 + 30 = 180 mph, ground speed going south
:
Write a time equation; time = dist/speed
:
time north + time back = 3 hrs
{{{d/120}}} + {{{d/180}}} = 3
multiply by 360 to cancel the denominators, results:
3d + 3d = 360(3)
5d = 1080
d = 1080/5
d = 216 miles to return point
;
:
Check this by finding the actual times:
216/120 = 1.8 hrs
216/180 = 1.2 hrs
------------------
total time: 3 hrs</PRE>