SOLUTION: A plane flies south for 2 hours and 30 minutes at a speed of 400 kilometers/hour. Then it turns and flies east for 1 hour and 45 minutes at a speed of 420 kilometer/hour. What is t

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A plane flies south for 2 hours and 30 minutes at a speed of 400 kilometers/hour. Then it turns and flies east for 1 hour and 45 minutes at a speed of 420 kilometer/hour. What is t      Log On

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Question 341277: A plane flies south for 2 hours and 30 minutes at a speed of 400 kilometers/hour. Then it turns and flies east for 1 hour and 45 minutes at a speed of 420 kilometer/hour. What is the plane's displacement from its initial position?
Answer by texttutoring(324) About Me  (Show Source):
You can put this solution on YOUR website!
You need to draw a triangle. One arm goes south, the other arm points east.

use the formula D=VT, where D=distance, V=velocity (speed) and T=time
Convert the times to hours with decimals (i.e. 2 hours and 30 minutes is the same thing as 2.5 hours)

South: D = (400)(2.5) = 1000 km
East: D = (420)(1.75) = 735 km

Now you should do Pythagorean theorem with 1000 as one arm, and 735 as the other arm.

Let the displacement = x

x^2 = 1000^2 + 735^2
x = 1241

So the plane is 1241 km away from where it started (as measured along the diagonal line).