Answer:
A) probability that at least x of them will require repairs is less than 0.5 is 4
Step-by-step explanation:
sample size, n = 20
p = success probability of toaster = 0.2
q = failure probability of toaster =1- p = 1- 0.2 =0.8
mean, , μ = n * p = 20 * 0.2 = 4
standard deviation, 
a) the probability that at least some of them require repairs < 0.5.
for
value of z = 0
we know 
from z table
X = 4
B) SECOND PART IS INCOMPLETE { DATA IS INCOMPLETE}
They could have assembled total 336 different possible crews.
<em><u>Explanation</u></em>
Total number of trained pilots is 9 and geologists is 4.
The crew should be consisted of 2 pilots and 1 geologist. That means, <u>2 pilots are chosen from total 9 and 1 geologist is chosen from total 4</u>.
Number of ways for choosing 2 pilots from 9
and
Number of ways for choosing 1 geologist from 4 
So, the total possible number of different crews they could have assembled 
3 strips of 2.5 feet can be cut from the 7.5 feet long roll of ribbon.
Step-by-step explanation:
<u>DATA:</u>
Length of strips Eli need is 2.5 feet long
Length of roll of ribbon is 7.5 feet long
Number of strips that can be cut from the 7.5 feet long roll is x
<u>SOLUTION:</u>
To determine how many strips can be cut, divide total length of roll of ribbon by the length of strips needed.
Number of strips that can be cut = 
x =
(expression)
x = 3 strips
Therefore, 3 strips of 2.5 feet can be cut from the 7.5 feet long roll of ribbon.
Key words: fraction
Learn more about fractions at
#LearnwithBrainly
use photomath for that that's way easier
Answer:
the answer is 28d + 42
Step-by-step explanation:
multiply what's on the brackets them add