Hello, having trouble figuring this one out. Its a general physics question.(adsbygoogle = window.adsbygoogle || []).push({});

question: Julie drives 100 mi to Grandmother's house. On the way to Grandmother's Julie drives half the distance at 40 mph and half the distance at 60 mph. On her return trip, she drives half the time at 40 mph and half the time at 60 mph.

a. What is Julie's average speed on the way to Grandmothers house?

b. What is her average speed on the return trip?

answers: a:48mph b: 50 mph

my work: i've tried to come up with these answers and i'm not sure how to get the answer for a.

for b, all i did was use this: d = r*t

so, 100 = ((40 + 60)t)/2

which gave me 50. so 50mph?

i'm confused, i'm not conviced that i'm attempting these correctly, but i know there not challenging when you set them up right.

any help please. Thankyou.

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# Homework Help: Physics: distance, rate, time problem

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