The 'template' for a quadratic function is:

, where <em>a</em> is the vertical stretch/compression factor.
If the <em>a</em> in f(x) is 2/5, then vertically stretching the function is done by multiplying the function by 2, making:
Consider the attached tree.
You start from the root, and with each level you create a sub-branch for each of the choices you have.
So, the root has two children, white and multigrain bread.
Each of those children has three children, because you have three meat choices
Each of those children has two children, because you have two cheese choices.
Then, you identify all the sandwiches by choosing a leaf, and read the label that lead you there.
For example, leaf number 4 represents a sandwich with white bread, turkey and provolone.
The hot tub takes in 1,520 watts everyday to keep its water warm. A kilowatt has 1,000 watts (hence kilo means 1,000). 1,520 divided by 1,000 equals 1.520. However, this isn't free electricity - Each kilowatt costs 8 cents or 0.08 of a dollar. 1.520 x 0.08 = 12.160 or $12.16. We aren't done yet! This hot tub runs for 4 months (and we are assuming these months exactly have 30 days each). 4 x 30 = 120. $12.16 x 120 = $1,459.20. In order to keep the hot tub running, you need to pay 1,459.20 for all the kilowatts of electricity it takes.
Answer:
73,084
Step-by-step explanation:
2.5(10^3) / 1.5(10^-6) = 2500/.0000015 = 1.67 seconds