Question 572025
d.	The amount of bacteria after n min if the initial amount of bacteria is q and the amount of bacteria triples every 30 seconds.  (Hint:  The answer should contain q as well as n.)

The time, n, is in minutues, so the amount triples every 1/2 min.
After the 1st 1/2 min., the amount
The expression will be of the form q(n) = q*3^(kn)
We need to find the coefficient, k:
After 1/2 min. the amount will be 3q, which means (1/2)k = 1 -> k = 2
So the equation is q(n)=q*3^(2n)
e.	The temperature t hour ago if the present temperature is 40F and each hour it drops by 3F.
Let T(t) = the temperature t hours ago
If the temperature drops 3F every hour, and if the current temp. is 40, then:
the temp. 1 hr ago was 43, the temp. 2 hrs ago was 46, etc.
The equation that describes this is T(t) = 40 + 3t
f.	Pawel’s total earnings after three years if the first year his salary was s dollars, the second year it was $5,000 higher, and the third year it was twice as much as the first year.
The total earnings will be s + s + 5000 + 2s = 4s + 5000
g.	The sum of three consecutive even whole numbers if the greatest is x.
If the largest number is x, then the other two numbers are x-2 and x-4
So the sum = x + x-2 + x-4 = 3x-6