Question 177011
if d=rt, then t=d/r __ the TIMES are the same


let w=wind


7/(180+w) = 5/(180-w)


"cross" multiplying __ 7*180 - 7w = 5*180 + 5w


adding 7w and subtracting 5*180 __ 2*180 = 12w


dividing by 12 __ 30 = w