Please help fast! Calculate the mean and explain the mean that would signify the entire population of fish by using this sample

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x

What is the sum of these mixed numbers 4 2/3+ 3 1/9

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.