<PRE><B>Question 588280</B>
Lisa&#39;s bike got a flat tire and she must walk the rest of the way to work.
 The bike was being ridden at 9 mph, and Lisa walks at a speed of 5 mph. 
The distance from home to work is 19 mi, and the total time for the trip was 3 hr.
 How far did she have to walk?
:
Let w = distance walked
the total distance given as 19 mi, therefore:
(19-w) = distance ridden
:
Write a time equation: time = dist/speed
:
bike time + walk time = 3 hrs
{{{((19-w))/9}}} + {{{w/5}}} = 3
Multiply by 45 to clear the denominators
45*{{{((19-w))/9}}} + 45*{{{w/5}}} = 45(3)
cancel the denominators
5(19-w) + 9w = 135
95 - 5w + 9w = 135
9w - 5w = 135 - 95
4w = 40
w = 40/4
w = 10 mi walked
:
:
Check this by finding the time of each
10/5 =2 hrs
9/9 = 1 hr
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total: 3 hrs</PRE>