SOLUTION: Katherine leaves home for school, riding her bicycle at a rate of 12miles/hr. Twenty minutes after she leaves, her mother sees Katherine's English paper on her bed and leaves to b

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Question 1159607: Katherine leaves home for school, riding her bicycle at a rate of 12miles/hr. Twenty minutes after she leaves, her mother sees Katherine's English paper on her bed and leaves to bring it to her. If her mother drives at 36miles/hr, how far must she drive before she reaches Katherine?
Found 3 solutions by ikleyn, josgarithmetic, MathTherapy:
Answer by ikleyn(52781) About Me  (Show Source):
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.

Head start is  12 mph * 1%2F3 of an hour = 4 miles.


Speed approaching is  36-12 = 24 mph.


Time to catch = 4%2F24 of an hour = 1%2F6  of an hour = 10 minutes.    ANSWER

Solved.


Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
20 minutes, same as 1%2F3hour;
12%281%2F3%29=4, four miles apart at the 'start'.

Mother's approach rate is 36-12=24 mph.

x, time to catchup
24x=4
x=4%2F24
x=1%2F6hour

Distance Mother traveled to catchup to Katherine:
36%2A%281%2F6%29=highlight%286%2Amiles%29

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
Katherine leaves home for school, riding her bicycle at a rate of 12miles/hr. Twenty minutes after she leaves, her mother sees Katherine's English paper on her bed and leaves to bring it to her. If her mother drives at 36miles/hr, how far must she drive before she reaches Katherine?
Let distance she should drive, be D

With matrix%281%2C3%2C+TIME%2C+%22=%22%2C+DISTANCE%2FSPEED%29, we get the following TIME equation: 

3D - 12 = D ------ Multiplying by LCD, 36

   - 12 = D - 3D

   - 12 = - 2D

Distance to be driven, or