I am not sure how to solve these problems :( can I get some help please?

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1 Answer
Jun 6, 2018

4 years old

Explanation:

This requires solving equations with logarithms:

#P(x)=31=90/(1+271e^(-0.122x))# and we want to solve for #x#

Rewriting:

#1+271e^(-0.122x)=90/31#

#e^(-0.122x)=(90/31-1)/271#

#e^(-0.122x)=59/8401#

Take the natural logarithm of both sides:

#ln(e^(-0.122x))=ln(59/8401)#

#-0.122x=ln(59/8401)#

#x=(ln(59/8401))/-1.22#

#x=4.06#

Rounded to a whole number would be 4 years old.