Question 184129
g= -200p^2 + 200p + 20 
what percentage of yeast gave an average weight gain of 60 grams ?
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60 = -200p^2 + 200p + 20

-200p^2 + 200p - 40 = 0

-5p^2 + 5p - 1 = 0

p = [-5 +- sqrt(25 - 4*-5*-1)]/-10

p = [-5 +- sqrt(5)]/-10

p = [-5 - sqrt(5)]/-10

p = 0.7236 = 72.36%
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Cheers,
Stan H.