Answer: 4 years
Step-by-step explanation:
A(0) has to be amount at start. Assume that's 5mg
Then A(t) = 5×(0.5)^(0.25t) = 5×2^(-t/4),
(also known as 5 exp(-λ t) with λ = ln(2)/4, incidentally).
We need to such that A(t) = 2.5mg, or 2^(-t/4) is 1/2, which happens when -t/4 is -1, or t is 4.
Associative property is the answer.
They give you the equation for Louis, and the table for Carl. Just find out Carl's equation by dividing the money earned by the time. 45 divided by 3 equals 15. Check it by the next time, 75 divided by 5 equals 15. So Carl's equation is y = 15x. 15x ( Carl's) greater than 12x ( Louis's).