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I am looking a probability question, the answer is given, but I cannot figure how they arrive at those figures.
An analysis of common household computers in a region reports that 33% of the computers of the computers are vulnerable to security penetrations through their telnet ports, 46% ftp ports, 73% printer ports. 18% are vulnerable through telnet and ftp ports, 36% through ftp and printer ports and 24% through telnet and printer ports and 12% through all their port.
Let's say their are 3 sets A, B and C. Let's say set A is telnet and B is Ftp and C printer. The answer given is (for A only)
p(A) = 0.03
p(A) π p( B) = 0.06
p(A) π p(C) = 0.12
p(A) π p(B) π(C) = 0.12
what i found out is if i add up all the values above, it gives .33 (33/100). My question how did they get from .33 to .03, .18 to .06 etc.
Determine the number of integer solutions of x1 + x2 + x3 = 6 where
a. xi > 0, 1 <= i <= 3
b. x1x2 >= 2 and x3 > 0
c. xi > 2, 1 <= i <= 3
the numbers and leter I are to be substrips.
for i : = 1 to 20 do
for j := 1 to i do
for k := i to j do
for m := 1 to k do
print (i * j)
I am not interested in an answer, I am able to type in to Java and see what the answer is. I want some ideas in relation to the approach in solving this problem in an examination.
P(n,2) = 90. What is n?
A certain ice cream store has 31 flavours of ice cream available. In how many ways can we order a dozen icreams cones if
(a) we do not want the same flavour more than once?
(b) a flavour may be orders as many as 12 times?
(c) a flavour may be ordered no more than 11 times?
consider the collection of all strings of length 10 made up from the alphabet 0, 1,2 and 3. How many of these strings have weigth 3? How many have weight 4? How many have even weight?
This is 2^(2k+3) + 1
= 4 x 2^(2k+1) + 1
= (3+1) x 2^(2k+1) + 1
= 3 x 2^(2k+1) + 3t
= 3(2^(2k+1) + t)
I am trying to understand the proove. Where does the 4 comes from? How is it decomposed to get (3 + 1)?
if n is a member of a set of positive integers, and n is odd, prove 8|(n^2-1)
(a) a and b are members of of the set of positive integers. If b|a and b|(a+2), prove that b = 1 or b = 2.
My solution
b * r = a
b * s = (a+2)
bs = (br + 2)
where do I go from here?
For all n E Z, n >= 0 prove that
(a.) 2^2n+1 + 1 is divisible by 3
(b.) n^3 +(n + 1)^3 + (n+2)^3 is divisible by 9
if t = 137486x225, where x is a single digit. Determine the value(s) of x such that 3|t. Which values of x make t divisible by 9?
My soluctions
x = 0 to make it divisible by 3
x = 4 to make it divisible by 9
you are correct, I was testing a number greater than 3.
Not quite certain, when I typed it on my system, the result is something like 1118.
Explain the concept of close form for me please.
Following the execution of this program segment, which value of n is printed?
N = 3
Sum = 0
While sum < 10,000 do
Begin
N = N + 7
Sum = sum + n
End
Print N
I am able to check my answer by typing in the code above. My question is, how do I approach this question in an examination setting? It would take forever to trace.
Allen writes the consecutive integers 1, 2, 3, .n on a black. Then Barbara erases one of these integers. If the average of the remaining integers 35 , what is n and what integer was erased?
My solution is 36. I am correct?
A lumberjack has 4n + 110 logs in a pile consisting of n layers. Each layer has two more logs than the layer directly above it. If the top layer has six logs, how many layers are there?
My solution n = 55
In how many ways can 11 identical horses on a carousel be painted so that three are brown, three are white, and five are black?
My solution p(11 3), p(11, 3), p(11 5)
Ten students enter a locker room that contains 10 lockers. The first student opens all the lockers. The second student changes the status (from close to open or vice versa) of every other locker, starting with the second locker. The third student then changes the status of every third locker. In general, 1<k<=10, the kth student changes the status of every kth locker. After the tenth student has gone through the lockers, which lockers are left open?
My solution is lockers 1, 4 and 9.
These are not my assignments. These are questions I am working on in preparation for my exams. Would you like me to post my solutions?
These are not my assignments, they are questions I have worked out and checking my answers. Would you like me to post my solutions?
A gym coach must select 11 senior players to play on a football team. If he can make his selection in 12,376 ways, how many seniors are eligible to play?
How many arrangements of the letters MISSISSIPPI have no consecutive Ss?
Over the internet, data are transmitted in structured blocks of bits called datagrams.
1. In how many ways can the can the letters DATAGRAM be arranged?
2. For the arrangements in part 1, how many has all three As together?
There are 4 letters a,c,f,g
1. How many permutations are there, list them.
2. How many combinations are there, list them.