The way to solve this question is to essentially reverse the equation I used in the other answer.
I would solve this with some theoretical values. If you start with 3, how long would it take for it to triple, or reach 9.
the equation would look like 9 = 3(2)^t/6, note how the instead of 1/2 it is now 2 in the parenthesis, as it doubles every 6 hours rather than halves every amount of hours.
When placed into an algebra calculator, the answer should be about 9.5 hours
So you need to find 15% of $27.38. To do this you can multiply 27.38 * .15 and get 4.107. Round to $4.11 and this is the tip. The total bill would be $31.49
Answer:

Step-by-step explanation:
The equation is

Solve for x
we know that

substitute

so

The answer to your question is 12b^2
Because 3-12 is -9 pal :)
32/45 is the answer I believe