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# Rate problem

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Elaine drives her car 180 miles and has an average of a certain speed. If the average speed had been 5mph more, she could have traveled 200 miles in the same length of time. What was her average speed?

Aug 21, 2021

#1
+12248
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What was her average speed?

Hello Guest!

$$xt=180ml\\ t=\dfrac{180ml}{x}\\ (x+5ml/h)t=200ml\\ t=\dfrac{200ml}{x+5ml/h}\\ \dfrac{x+5ml/h}{200ml}=\dfrac{x}{180ml}\ |\ \times ml$$

$$180x+900ml/h=200x\ |\ -180x\\ 900ml/h=20x\ |\ :20$$

$$x=45ml/h$$

Her average speed was 45ml/h.

!

Aug 21, 2021