SOLUTION: An actress has to be on set, which is 21 miles away at 7am. If she wakes up at 5:30 am and does her make up for 48 minutes, how fast must she drive to get on to work on time? * ste

Question 982009: An actress has to be on set, which is 21 miles away at 7am. If she wakes up at 5:30 am and does her make up for 48 minutes, how fast must she drive to get on to work on time? * step by step method please! THX!
Found 2 solutions by jim_thompson5910, MathLover1:
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Add 5:30 to 0:48

5:30
0:48
-----
6:18

So she does her makeup, and when that is finished, she takes off at 6:18 am.

-------------------------------------------------------

The time difference from 6:18 am to 7:00 am is 42 minutes, which is 42/60 = 0.7 hrs

She must drive 21 miles for 0.7 hours

d = 21
r = unknown
t = 0.7

Use the equation d = r*t to solve for r

d = r*t

21 = r*0.7

21/0.7 = r*0.7/0.7 divide both sides by 0.7 to isolate r

30 = r

r = 30

She must drive at least 30 mph to make it on time. I put "at least" in there to mean that if she drives faster than 30 mph, then she'll have a bit of time to spare.
Answer by MathLover1(20849) (Show Source): You can put this solution on YOUR website!

distance is:

time:
from to is
subtract the time she need for make up

so, to drive on set she has
since , we have
.........substitute for and for

so, she must drive to get on to work on time

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