If one half-life is the amount of time it takes for a radioactive isotope to decay by a factor of 2, approximately which percent describes how much of the initial quantity of a substance would
remain after 2.3 half-lives?

a. the residual plot for model 1 has a random pattern and is a good fit for the data.

okay..i will pick 8!

the revenue of the fitness center, y, is the product of two factors: the number of members and the fee paid by each member. there are 320 members now, but number of members goes down by 10 for each $5 increase in fees, so if x is the number of $5 price increases then members is equal to (320 - 10x). since the fee is currently $45, and the fee increases by $5 for every price bump x, the fee is given by (45 + 5x). so, revenue y is given by y = (320 - 10x)(45 + 5x).

answer: your answer is a