Answer:
There is a 99.99998% probability that at least one valve opens.
Step-by-step explanation:
For each valve there are only two possible outcomes. Either it opens on demand, or it does not. This means that we use the binomial probability distribution to solve this problem.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinatios of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
In this problem we have that:
Calculate P(at least one valve opens).
This is
Either no valves open, or at least one does. The sum of the probabilities of these events is decimal 1. So:
So
Finally
There is a 99.99998% probability that at least one valve opens.
Well let's see:
The first letter can be any one of 26 .
For each one . . .
The second letter can be any one of the remaining 25.
For each one . . .
The third letter can be any one of the remaining 24.
For each one . . .
The two digits can be any number from 01 to 98 ...
except 11, 22, 33, 44, 55, 66, 77, or 88. (No repetition.)
There are 90 of them.
So the total number of possibilities is (26 · 25 · 24 · 90) .
When I multiply that out, I get 1,404,000 .
I don't know how you got your number, so I can't comment on your
method, but I did find something interesting about your number:
If I assume that you did the three letters the same way I did, then
if I divide your number by (26·25·24), the quotient will show me
how you handled the two digits.
1,263,600 / (26·25·24) = 81 .
That's very intriguing, because it's so close to the 90 sets of digits
that I used. But I don't know what it means, or if it means anything
at all.
Answer:
60%
Step-by-step explanation:
we know that
the price per share of a stock decreased from $90 per share to $36 per share
In this problem
$90 represent the 100%
so
using proportion
Find out what percentage represent the difference of ($90-$36)
($90-$36)=$54
Let
x ----> the percentage of the difference
You can do 4 to the second power and 4×4 equals 16