Question

The amount of water left in a cup after sitting outside in the sun can be modelled by the function A(t) = 120((12)^t/3 where A(t) represents the amount of water in mL and t represents the time passed in hours

a) write down how much water will be there after 24 hours. Round your answer to 2 decimal places.

b) write down how long it takes for the amount of water to get to 15 mL

Answer 1

See comment in your previous post of this

Answer 2

can u give link to that

Answer 3

I had stated :


"Check the typing of your equation.

The way it stands, it would be an increasing function, not representing the "amount of water left .." of your question."

I don't know why that reply did not show up.
Perhaps I didn't even click on "submit", need another coffee.

Answer 4

again? Why do you always start a whole new post when following up? And why do you not even correct your fractions and mismatched parentheses?
Clearly you should have written
A(t) = 120*(1/2)^(t/3)
(a) 24 hours is 8 half-lives, so 1/256 is left: 120/256 = ___
(b) now just solve
120*(1/2)^(t/3) = 15
15/120 = 1/8, so that is 3 half-lives, so t=9