# help,math

posted by
**jas20** on
.

can some set the equation up for me.

Science and medicine. A plane flies 720 mi against a steady 30-mi/h headwind and then returns to the same point with the wind. If the entire trip takes 10 h, what is the plane’s speed in still air?

i thought it was this set up but its not:

(720)/(30)=(x)/(10)

The correct equation that you need to solve is:

720/(V-30) + 720/(V+30) = 10

V-30 is the planes ground speed flying inti the wind, and V+30 is the ground speed with the 30 mph tail wind. What I wrote was the total time required for both trips.

DRAWLS ,

YOU JUST LOST ME....HOW AM I SUPPOST TO SOLVE FOR THIS

720/(V-30) + 720/(V+30) = 10

Get a common denominator of

(v-30)(v+30)

then multiplying both sides by that, then

720(V+30) + 720(V-30)= 10(v-30)(v+30)

then multily out, and solve for v.

During rush hour, Fernando can drive 35 miles using the side roads in the same time that it takes to travel 30 miles on the freeway. If Fernando’s rate on the side roads is 9 mi/h faster than his rate on the freeway, find his rate on the side roads.