SOLUTION: Anna and Bill walk the same route from home to school. They don't leave at the same time. Anna sets off first followed by bill 5 minutes later. The distance from their home to the

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Question 747807: Anna and Bill walk the same route from home to school. They don't leave at the same time. Anna sets off first followed by bill 5 minutes later. The distance from their home to the school is 1.2 KM. Anna walks at a steady speed of 1 m/s. Bill walks faster at 1.5 m/s.
a) Draw their distance -time graphs.
b) How many seconds does it take Anna to complete the walk to school?
c) How long does it take Bill to reach the school?
d) How long does it takes Bill to catch up with Anna and how far are they from the school when he does?

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Plot distance in meters on the vertical
axis and time in seconds
on the horizontal
Anna's head start is +1%2A300+=+300+ m ( 5 min is 300 sec )
Let +t+ = the time in seconds started when Bill leaves
Let +d+ = the distance in meters for the whole route
Anna's equation:
(1) +d+-+300+=+1%2At+
Bill's equation:
(2) +d+=+1.5t+
---------------
(1) +d+=+t+%2B+300+
------------------
Here's the plot- note that +d+=+1200+ m is as far as they will go.
+graph%28+500%2C+500%2C+-500%2C+1300%2C+-100%2C+1500%2C+1.5x%2C+x+%2B+300+%29+
The line that starts at +0+ is Bill's
The line that starts at +d+=+300+ is Anna's
-----------------
Anna:
+d+=+t+%2B+300+
+1200+=+t+%2B+300+
+t+%2B+300+=+1200+ sec is Anna's time to get to school
------------------
Bill:
+d+=+1.5t+
+1200+=+1.5t+
+t+=+800+ sec is Bill's time to get to school
----------------
Bill catches anna when
+t+%2B+300+=+1.5t+
+.5t+=+300+
+t+=+600+sec+
---------------
When +t+=+600+ sec,
+d+=+1.5%2A600+
+d+=+900+ m
----------------