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Goose a variable and write an equation to solve the situation. Kevin drive 320 miles to a mountain resort. His return trip took 20 minutes longer because his speed returning was 4 mr/h slower than his speed going.

Answer :

Mhanifago

Answer:

  • 320/x + 1/3 = 320/(x - 4)
  • x = 64 mph

Step-by-step explanation:

Let the speed is x.

We have equation:

  • 320/x + 20/60 = 320/(x - 4) ⇒ 320/x + 1/3 = 320/(x - 4)

To solve we need to get rid of fraction:

  • 320(x - 4) + 1/3x(x - 4) = 320x
  • x² - 4x - 3840 = 0
  • x² - 4x + 4 = 3844
  • (x - 2)² = 62²
  • x - 2 = 62
  • x = 64

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