Two planes left simultaneously from the same airport and headed in the same direction towards another airport 3600 km away. The speed of one of the planes was 200 km/hour slower than the speed of the other plane, and so it arrived at its destination 1.5 hours after the faster plane. Find the speeds of both planes.

Respuesta :

Answer: The speed of the faster lane is 800 km/hour and the slower plane is 600 km/hour

Step-by-step explanation:

The speed of the faster plane is 800 km/h and the speed of the slower plane is 600 km/h.

The given parameters:

Distance traveled by both planes, d = 3600 km

  • Let the speed of the faster plane = v
  • The speed of the slower plane, u = v - 200 km/h
  • Let the time taken for the faster plane = t hours
  • Time taken for the slower plane to arrive = t + 1.5 hours

The distance traveled by both planes is the same;

d = u(t + 1.5) ---(1)

d = (v - 200) (t + 1.5)

3600 = vt + 1.5v - 200t  - 300  

d = vt  ----(2)

3600  =  vt

[tex]v = \frac{3600}{t}[/tex]

[tex]3600 = \frac{3600}{t} t \ +\ 1.5 (\frac{3600}{t} ) \ - \ 200 t - 300\\\\3600 = 3600 + \frac{5400}{t} - 200t - 300\\\\300 = \frac{5400}{t} - 200t\\\\300t = 5400 - 200t^2\\\\200t^2 +300t - 5400 = 0\\\\2t^2 + 3t- 54= 0\\\\(2t - 9)(t + 6)= 0\\\\t = 4.5 \ \ or \ \ -6 \ \\\\t = 4.5 \ hours[/tex]

The speed of the faster plane is calculated as;

[tex]v = \frac{3600}{t} \\\\v = \frac{3600}{4.5} \\\\v = 800 \ km/h[/tex]

The speed of the slower plane is calculated as follows;

[tex]u = v- 200\\\\u = 800 - 200\\\\u = 600 \ km/h[/tex]

Learn more about distance and speed here:  https://brainly.com/question/2854969

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