Answer:
a) 23.76%
b) 7.8%
Step-by-step explanation:
a) probability that a failure is due to loose keys.
loose key failure (27%) comes under mechanical failure(88%)
hence, probability that a failure is due to loose keys= 0.27×0.88= 0.2376= 23.76%
b) probability that a failure is due to improperly connected wire which comes under electrical failure = 0.12×0.13
probability that a failure is due to poorly welded wires which comes under electrical failure= 0.52×0.12
now, the probability that a failure is due to improperly connected or poorly welded wires. = 0.12(0.52+0.13)= 0.078= 7.8%
The area of the bare spot the gardener needs to replant is 201 square feet
Step-by-step explanation:
We have to find the area of the circular bare spot
Given
Radius of bare spot = r = 8 inches
The formula for area of a circle is given by:

putting the value

Rounding off to nearest foot
201 ft^2
Hence,
The area of the bare spot the gardener needs to replant is 201 square feet
Keywords: Area, radius
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Answer:
d
Step-by-step explanation:
just took the test
Approximately 1718 have a score within that range.
We calculate the z-score for each end of this spectrum:
z = (X-μ)/σ = (2.5-3.1)/0.3 = -0.6/0.3 = -2
Using a z-table (http://www.z-table.com) we see that the area to the left of, less than, this z-score is 0.0228.
For the upper end:
z = (3.7-3.1)/0.3 = 0.6/0.3 = 2
Using a z-table, we see that the area to the left of, less than, this z-score is 0.9772.
The probability between these is given by subtracting these:
0.9772 - 0.0228 = 0.9544.
This means the proportion of people that should fall between these is 0.9544:
0.9544*1800 = 1717.92 ≈ 1718