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.
Answer:
The population proportion is estimated to be with 99% confidence within the interval (0.1238, 0.2012).
Step-by-step explanation:
The formula for estimating the population proportion by a confidence interval is given by:

Where:
is the sample's proportion of success, which in this case is the people that regularly lie during surveys,
is the critical value needed to find the tails of distribution related to the confidence level,
is the sample's size.
<u>First</u> we compute the
value:

<u>Next</u> we find the z-score at any z-distribution table or app (in this case i've used StatKey):

Now we can replace in the formula with the obtained values to compute the confidence interval:

I got:
-2(2f-3g)
explanation:
used communicative property
Down payment is 20% of the price of the home. Since the couple saved $35,000, and assuming they will pay the whole money as down payment, the highest priced home they can get is a price whose 20% is $35,000.
We can setup an equation in x (being the price of home) to get the price of the most expensive home they can buy.
<em>Which number (x) , multiplied by 20%, is equal to $35,000?</em>
<em>
</em>
So, the most expensive house they can buy is worth $175,000.
ANSWER: $175,000
Answer:x=(y-6)/3
Step-by-step explanation: