What is the quotient of 6 and -1/2? <br> A. -12<br> B. -1/2<br> C.1/12<br> D. 12

A certain brand of refrigerator has a useful life that is normally distributed with mean 10 years and standard deviation 3 years

juin [17]

Answer: 0.55567

Step-by-step explanation:

Given : A certain brand of refrigerator has a useful life that is normally distributed with mean 10 years and standard deviation 3 years. The useful lives of these refrigerators are independent.

i.e.

$\mu=10\text{ years}\\\sigma=3\text{ years}$

Let $X_1$ and $X_2$ are two randomly selected refrigerator's life whose sum will exceed third selected refrigerator $X_3$ .

So that, $X =X_1+X_2-1.9\times X_3$

Mean $=E(X_1)+E(X_2)-E(X_3)=10+10-1.9\times10 =1$

Standard deviation = $\sqrt{(Var(X_1)+Var(X_1)+Var(X_1))}$

$=\sqrt{(3^2+3^2+(1.9\times3)^2)}$

$=7.1056315694$

Z-score : $z=\dfrac{X-E[x]}{\sqrt{Var[x]}}=\dfrac{0-1}{7.0156315694}\approx-0.14$

Now , The probability that the total useful life of two(i..e n=2) randomly selected refrigerators will exceed 1.9 times the useful life of a third randomly selected refrigerator would be :-

$P(Z>-0.14)=P(Z$

Hence, the required probability is 0.55567.

3 0

3 years ago

135% as a fraction or a mixed number fully simplified please

solong [7]

Answer:

135% = 27/20 = 17/20 as a fraction

Step-by-step explanation:

Step 1: Write down the percent divided by 100 like this:

135% = 135/100

Step 2: Multiply both top and bottom by 10 for every number after the decimal point:

As 135 is an integer, we don't have numbers after the decimal point. So, we just go to step 3.

Step 3: Simplify (or reduce) the above fraction by dividing both numerator and denominator by the GCD (Greatest Common Divisor) between them. In this case, GCD(135,100) = 5. So,

(135÷5)/(100÷5) = 27/20 when reduced to the simplest form.

As the numerator is greater than the denominator, we have an IMPROPER fraction, so we can also express it as a MIXED NUMBER, thus 135/100 is also equal to 1 7/20 when expressed as a mixed number.

6 0

2 years ago

What is the graph's approximate rate of change? -1/2 12 2 -2

geniusboy [140]

The answer is 1/2 i did the test and got it right can i get brainliest please

5 0

3 years ago

Carla and Mia own neighboring cornfields. Carla harvested 9/10 of an acre of corn on Monday and Mia harvested 1/2 of an acre. Ho

viva [34]

Answer:

2/5 of an acre

Step-by-step explanation: