Answer:
11. a. yes b. no
12. i. yes ii. yes
13. a. 31/35 b. 1 5/9 c. 1/30 d. 1/15
Step-by-step explanation:
11. add them
12. estimate
13. add or subtract
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.
Answer:
Um I will report ur answer
Step-by-step explanation:
A question:
(5.3 x 10 to the 6th power) + 8.2 10 to the 6th power)
A solution:
Multiply 10 x 10 6 times to get rid of the two powers.
(5.3 x 1,000,000) + (8.2 x 1,000,000)
Multiply inside the parenthises.
(5,300,000) + (8,200,000)
Add:
13,500,000.
A answer:
13, 500,000.
B question:
(6.5 x 10 to the 7th power) / (5 x 10 to the 3rd power)
B solution:
Again, get rid of the powers.
(6.5 x 10,000,000) / (5 x 1,000)
Multiply inside the parenthesis:
(65,000,000) / (5,000)
Divide:
13,000
B answer:
13,000.
C question:
(4.6 x 10 to the 6th power) (3 x 10 to the 5th power) / (2 x 10 to the 7th power)
C solution:
Get rid of powers:
(4.6 x 1,000,000) (3 x 100,000) / (2 x 10,000,000)
Multiply:
(4,600,000) (300,000) / (20,000,000)
multiply in the left side:
(1,380,000,000,000) / (20,000,000)
divide:
69,000
C answer:
69,000