SOLUTION: At 11am, billy and leon set off towards each other from different places 32km apart. billy cycled at 20 km per hour and leon walked at 5km per hour. draw distance time graphs of t

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Question 265006: At 11am, billy and leon set off towards each other from different places 32km apart. billy cycled at 20 km per hour and leon walked at 5km per hour.
draw distance time graphs of their journeys on the same grid to find out:
1. the time at which they met
2. the time at which they are 12km apart.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
At 11am, billy and leon set off towards each other from different places 32km apart. billy cycled at 20 km per hour and leon walked at 5km per hour.
draw distance time graphs of their journeys on the same grid to find out:
:
referenced to Billy's starting point
d = distance from the reference point
t = time (hrs)
Two equations
d = 20t; (Billy, Red)
d = 32 - 5t; (Leon, Green)
Graphing the two equations. Time on the x axis, distance from Ref on y axis
+graph%28+300%2C+200%2C+-4%2C+8%2C+-10%2C+40%2C+20x%2C+32-5x%29+
1. the time at which they met
We can estimate using the graph, but we calculate it exactly (equal dist from ref)
20t = 32 - 5t
20t + 5t = 32
25t = 32
t = 32%2F25
t = 1.28 hrs or 1 hr + .28(60) ~ 17 minutes
11 am + 1:17 = 12:17 pm
:
2. the time at which they are 12km apart.
Subtract Billy's equation from Leon's equation, find t
(32-5t) - 20t = 12
-25t = 12 - 32
-25t = -20
t = 20%2F25
t = .8 hrs, .8(60) = 48 min which would be 11:48 am