An airplane travels 4362 km against the wind in 6 hours and 5322 km with the wind in the same amount of time. what is the rate of the wind? Choose the correct answer
A) 60km/hr
B) 70km/hr
C) 80km/hr
D) 90km/hr
E) 100km/hr
Let the speed of the air plane in still air be x km/hr   And the speed of the wind be y km/hr.   Then speed of the airplane going with the wind = (x + y) km/hr   and speed of the airplane going against the wind = (x - y) km/hr.   We know that,   Distance = Speed ? Time   or, Speed = Distance   Time   According to the problem,   An airplane travels 4362 km against the wind in 6 hours   x - y = 4362/6   or, x - y = 727 ----------- (1)   Again, the airplane travels 5322 km with the wind in the same amount of time i.e. 6 hours   x + y = 5322/6   or, x + y = 887 ----------- (2)   Now add (1) and (2) we get,   x - y = 727   x + y = 887   2x = 1614   or, 2x/2 = 1614/2, (Divide both sides by 2)   or, x = 807   Now substitute the value of value of x = 807 in equation (2) we get,   807 + y = 887   -807 -807, (Subtract 407 from both sides)   y = 80   Answer:Rate of the wind = 80km/hr   correct answer 80km/hr
<result>C</result>
An airplane travels 4362 km against the wind in 6 hours and 5322 km with the wind in the same amount of time. what is the rate of the wind?