Answer:
The speed of air in still air =570 mph and
speed of wind = 40 mph
Step-by-step explanation:
Given that plane travelled 2135 miles in 3.5 hours with the wind.
Let the velocity of plane be x and that of wind be y.
Then with the wind speed =x+y and
against the wind the speed = x-y
Use distance = time x speed
Since travelled 2135 miles in 3.5 hours we have
2135 = 3.5 (x+y) ... i
Similarly with x-y speed it travelled 1855 miles in 3.5 hours
i.e. 1855 = 3.5(x-y) ... ii
Solving these two we can get x and y
i-ii gives
3.5y+3.5y = 2135-1855 = 280
i.e. 7y =280
Or y = 40 mph
Substitute in i
3.5(x+40) = 2135
x+40 = 610
x = 570 mph
Hence the speed of air in still air= x =570 mph and
speed of wind = 40 mph
