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3 years ago

How can you solve multiplication fast with no calculator?

1 answer:

4 0

You study as much of the times tables as possible and once you have that information stored in your Brain, you use mental math. You can write it down on paper but that’s pretty time consuming if you go at a slow pace.

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A boiler has five identical relief valves. The probability that any particular valve will open on demand is 0.93. Assume indepen

noname [10]

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.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinatios of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

In this problem we have that:

$n = 5, p = 0.93$

Calculate P(at least one valve opens).

This is $P(X \geq 1)$

Either no valves open, or at least one does. The sum of the probabilities of these events is decimal 1. So:

$P(X = 0) + P(X \geq 1) = 1$

$P(X \geq 1) = 1 - P(X = 0)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{5,0}.(0.93)^{0}.(0.07)^{5} = 0.0000016807$

Finally

$P(X \geq 1) = 1 - P(X = 0) = 1 - 0.0000016807 = 0.9999983193$

There is a 99.99998% probability that at least one valve opens.

5 0

2 years ago

Read 2 more answers

Whats is 1+1 <br><br> *i cant figure it out *

seropon [69]

Answer:

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

What ordered pair is a solution of the equation?<br><br> y=-2x-5

ioda

$\sf \underline{Answer:}$

Pick any value for x, like x = 0, plug it into the equation, and get the value for y. For x = 0,

2(0) + y = 5

y = 5

The ordered pair is (0,5). Find other ordered pairs using the same reasoning.

3 0

1 year ago

Read 2 more answers

The population P of birds in an area is modeled by the exponential model

Tems11 [23]

(B)Decreasing is the answer

3 0

2 years ago

A test of H0: p = 0.5 versus Ha: p > 0.5 has the test statistic z = 1.15. Part A: What conclusion can you draw at the 5% sign

Nadya [2.5K]

Answer:

Part A: The null hypothesis failed to be rejected.

Part B: The null hypothesis failed to be rejected.

Step-by-step explanation:

We have an hypothesis test with null and alternative hypothesis H0: p = 0.5 versus Ha: p > 0.5, which has the test statistic z=1.15.

Part A: If the significance level is 0.05, the conclusion depends on the P-value.

If the P-value is below 5%, the null hypothesis is rejected.

The P-value for this right-tailed tes and z=1.15 is:

$P-value=P(z>1.15)=0.125$

The P-value is bigger than the significance level, so the effect is not significant and the null hypothesis is failed to be rejected.

Part B: In this case, the significance level is 0.01 and, as the alternative hypothesis is defined with an unequal sign, the test is two-tailed.

This changes the way we calculate the P-value, as we need to compute the two tails.

The P-value is:

$P-value=2P(z>1.15)=0.25$

The P-value is bigger than the significance level, so the effect is not significant and the null hypothesis is failed to be rejected.

5 0

2 years ago