Question 332174
2520km in 6 hours with a tailwind, but only 1620 km with a headwind in the same time.
let speed of plane be x
speed of wind be y
..
{{{distance / speed = time}}}
with tailwind speed = x+y
with headwind speed = x-y
..
Tailwind
{{{2520/(x+y)=6}}}
2520=6x+6y
divide by 6
420= x+y..................1
Headwind
{{{1620/(x-y)=6
6x-6y=1620
divide by 6
x-y=270..................2
add equation1 & 2 to eliminate y
x+y+x-y=420+270
2x=690
x=395 mph speed of plane
..
x+y=420
395+y=420
y=420-395
y=25 mph speed of wind
..