<PRE><B>Question 563802</B>
You jog at a speed of 6 miles per hour for 20 minutes, and you walk at a speed of 4 miles per hour for t minutes.
 If your combined jogging and walking distance is 3 miles, for how long did you walk?
:
We are dealing with mph, so we have to put the min over 60
:
Write a distance equation; dist = speed * time
:
Dist at 6mph + dist at 4mph = 3 miles
6*{{{20/60}}} + 4*{{{t/60}}} = 3
Cancel
{{{20/10}}} + {{{t/15}}} = 3
mult by 30 to clear the denominators, results
3(20) + 2t = 30(3)
60 + 2t = 90
2t = 90 - 60
2t = 30
t = 15 min at 4 mph</PRE>