Use the compound interest formula: A=P(1+i)^t.
P is the initial amount of the drug, 0.3ml.
i is - 0.0035.
t is in seconds.
You'll get:
A=0.3(1-0.0035)^t.
Sub in any value on t to find out how many ml are left t seconds after injection.
The 0.65 second injection time does not seem to be relevant as the question clearly states that the exponential decay starts AFTER the injection is completed.
7x - 5 = 0
7x = 5
x = 5/7
--------------------------
For the range:
5, infinity
If for is four then x-4=8
thus would make x 12
Step-by-step explanation:
a).
n! is

(n-3)! is

If we divide the two, everything behind (n-3) will just cancel out so we would be left with only

So the answer to a is

b
Permutations formula of P(6,4) is
6!/(6-4)!, or 6!/2!.

Then we divide by 4!

The answer to b is 15