I believe you are referring to the half-life formula, which is used to calculate the half-life (when the substance drops to half of its original amount) of radioactive substances. The equation is as follows:

<em>A</em> is the remaining amount
<em>P</em> is the initial amount
<em>t</em> is the time that has passed
<em>h</em> is the half-life of the substance
When plugging values into the equation, make sure that <em>t </em>and <em>h </em>are both measured in the same unit (e.g. <em>t </em>days and <em>h </em>days), as well as <em>A </em>and <em>P</em>.
Answer:
Without taxes, the price will be $359.99
Step-by-step explanation:
You take the original price then divide it by ten. Then you multiply that number by 2 to get what 20% of 449.99 is. You then subtract that number from from 449.99. At least I think so. There are other ways to go faster but this is the easiest to understand.
Answer:
A and D have whole grid squares that are the same size and aren't over lapping
C has overlapping grid squares making it hard to count
B can't be used to find area because some of the grid squares are different sizes
You still could use B because four of the smaller squares seems to be equivalent to one of the larger squares
Step-by-step explanation: