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Sample submitted
solution:
From:
Christina, age 13
Yusra, age 13
School: Issaquah Middle School, Issaquah,
Washington
1. Explain the meaning
of the red, purple, and green lines, as
well as the red line segment described above.
The red line is how the distane Sally
and Suzie have traveled. The purple line
Suzie's rate of riding. The green line is
the rate of Sally's riding. The red line
segment described above represents the diffrence
of rate between the two girls.
2. Suppose that Suzie passes
the house 10, 20, or 40 minutes later than
Sally. Read the graph to find out how far
the house was from the school in each case.
10 minutes: 2.5 miles
20 minutes: 5 miles
40 minutes: 10 miles
3. (BONUS) Write an expression
(a distance, rate, time function) that allows
Sally to find out how far the house was
from the school, if she knows only the time
difference between when she and Suzie passed
the house. Please explain how you came up
with the expression.
d=distance r=rate t=time d=rt 2.5=r10 r=1/4
5=r20 r=1/4 10=r40 r=1/4 d=1/4t So after
substituting the distance and time into
the d=rt equation we found that ther was
a 1/4 rate. So r=1/4.
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