Scrub a dub toothbrush is are four dollars each there is a 10% discount but there is also a 6% sales tax after the discount is a
1 answer:
You might be interested in
Answer:
1/3 is the answer.
Step-by-step explanation:
Tanya prepared 4 different letters to be sent to 4 different addresses.
To solve this we can do the following:
The probability that the 1st letter is in the right envelope is =
The probability that the 2nd letter is in the wrong envelope is =
The probability that the 3rd letter is in the wrong envelope is =
The probability that the 4th letter is in the wrong envelope is = 1
So, the answer becomes: =
As we need 4 correct letters in the envelope, we will multiply by 4:
Lagrange multipliers:
(if 
)
(if )
(if 
)
In the first octant, we assume
, so we can ignore the caveats above. Now,
so that the only critical point in the region of interest is (1, 2, 2), for which we get a maximum value of
.
We also need to check the boundary of the region, i.e. the intersection of
with the three coordinate axes. But in each case, we would end up setting at least one of the variables to 0, which would force 
, so the point we found is the only extremum.
In the first octant, we assume
so that the only critical point in the region of interest is (1, 2, 2), for which we get a maximum value of
We also need to check the boundary of the region, i.e. the intersection of