Michelle and Michael are preparing for a bike race. Michelle rode 20 miles last week and plans to ride 35 miles per week until the race. Michael rode 50 miles last week and plans to ride 25 miles per week until the race.

Part A
Chorus:
Expontential growth = b*a^x 
b = 15
a = 1.12              (a= r+1), r = 12%

Which gives a function of f(x) = 15*1.12^x 

Band
Linear growth = ax+b
a = 2
b = 30

Which gives a function of g(x)=2x+30

Part B:
f(9) = 15*1.12^9 = 41.59
g(9) = 2*9+30 = 48

Part C:
This is probably problem solving, where you're allowed to use calculators and other softwares.

Therefore you can use different softwares, and make f(x) = g(x).
I did this, and got it to 10.95427141

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