Find Time

Sarah leaves Seatle for New York in her car, averaging 80 mph across the country. One hour later a plane leaves Seatle for New York following the same route and flying 400 mph. How long will it be before the plane OVERTAKES the car?

Let me see.

Sarah:

rate = 80 mph

time = x

Plane:

rate = 400 mph

time: x + 1, where 1 = one hour later

Set Up:

80x = 400(x + 1)

You say?

 

if time=x

time: x + 1 goes with Sara (means she has 1h advantage)
then
80(x + 1) = 400*x

 

Ok. Thanks for the correction.