wind speed

Question

an airplane can fly 1216 miles from city A to city B in 4 hours with the wind. The same airplane take 8 hours against the wind for the return trip. What is the speed of the wind?

Answer 1

there are different approaches to the problem

1216=(r+w)4

1216=(r-w)=8

simplify

304=r+w

152=r-w

add

456=2r

r=228, the rate of the plane

304=228+w

304-228=w

w=76, the rate of the wind

also,...

1216=(r+w)4

1216=(r-w)8

(r+w)4=(r-w)8

r+w=(r-w)2

r+w=2r-2w

3w=r

1216=(3w+w)4

1216=(4w)4

1216=16w

1216/16=w

w=76 again

 

Answer 2

d = r · t

 

1216 = (p + w)4

1216 = (p - w)8

 

1216 = 4p + 4w

1216 = 8p - 8w

 

2432 = 8p + 8w

1216 = 8p - 8w

 

1216 = 16w

76 = w