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.

Let
and
are two randomly selected refrigerator's life whose sum will exceed third selected refrigerator
.
So that, 
Mean 
Standard deviation =


Z-score : ![z=\dfrac{X-E[x]}{\sqrt{Var[x]}}=\dfrac{0-1}{7.0156315694}\approx-0.14](https://tex.z-dn.net/?f=z%3D%5Cdfrac%7BX-E%5Bx%5D%7D%7B%5Csqrt%7BVar%5Bx%5D%7D%7D%3D%5Cdfrac%7B0-1%7D%7B7.0156315694%7D%5Capprox-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 :-

Hence, the required probability is 0.55567.
The subtraction equation that represents the problem is ( h-477)metres
<h3>Subtraction problem</h3>
Given the following information
- The original height of the helicopter = h meters
If the traffic helicopter descends to hover 477 meters above the ground, then the original height of the helicopter will be:
Original height = h - 477 (Since it is descending)
Hence the subtraction equation that represents the problem is ( h-477) meters
Learn more on subtraction problem here brainly.com/question/220101
7 times 48 is 336
7 times 47 is 329
332/7= 47.4
7/332=.021
Answer: y= -5x - 1
y = -5.2 + 7
Step-by-step explanation: y= -5x - 1 has 3. y = -5.2 + 7 has 1
Answer:
485
Step-by-step explanation:
Q(-9) = 6(-9)² - 1 = 6×81 - 1 = 486 - 1 = 485