For A well I can't do a graph ,but to do it you would start at 50 going up 25 each week
For B it would be 300 because 25×10=250 plus the 50 from his grandmother he would have 300
You want to find the time <em>t</em> such that

Divide both sides by $200 :

Take the logarithm of both sides:

Divide both sides by 0.04 and solve for <em>t</em> :

It is 0 because anything multiplied by 0 is 0.
C = 2πr
r = radius
c = circumference = 18
Plug in the corresponding numbers with variables.
18 = 2πr
Isolate the r. Divide 2 and π from both sides
(18)/2π = (2πr)/2π
9/π = r
C/π = r is your formula to finding r.
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