Question

Eric´s mother drives to work in 20 min when driving at her usual speed. When traffic is bad, she drives 10 miles per hour slower, and the trip takes 10 minutes longer. What is Eric´s mother´s usual speed?

Answer 1

Answer:

30

Step-by-step explanation:

I could be wrong

Answer 2

The usual speed of Eric's mother is 4 miles per hour .

Eric´s mother drives to work in 20 min when driving at her usual speed.

Let the usual speed of Eric's mother be "u"  miles per hour (mph)

When the traffic is bad she drives 10 miles per hour slower.

The speed of Eric's mother when the traffic is bad = u-10 mph

The time taken by Eric's mother when the traffic is bad = 30 min

$\rm Displacement = \dfrac{Velocity }{Time }$

The considering the displacement  in both  the cases is same hence we can

say that

$\rm \dfrac{u}{20/60} = \dfrac{-(u-10)}{30/60} \\\rm 3u = -2u +20 \\5u = 20 \\u = 4$

So the usual speed of Eric's mother is 4 miles per hour .

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https://brainly.com/question/23294846