Answer:
92.65 % light bulbs last less than 2080 hours
Step-by-step explanation:
We are given that The amount of time a certain brand of light bulb lasts is normally distributed
Mean =
Standard deviation =
We are supposed to find What percentage light bulbs last less than 2080 hours, to the nearest tenth
Z=1.45
Refer the z table for p value
p value = 0.9265
Hence 92.65 % light bulbs last less than 2080 hours
Answer:
13
Step-by-step explanation:
2(x-1)+8=4x-20
distribute 2
2x-2+8=4x-20
2x+6=4x-20
subtract 2x from both sides
6=2x-20
add 20 to both sides
26=2x
divide both sides by 2
x=13
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The standard deviation of the set is 5.2
To find standard deviation, we take the square root of the variance.
It would the answer C choice
Old scale : 1 in. to 3 ft.
length is 9 in.....9 * 3 = 27 ft (old scale length)
width is 6 in......6 * 3 = 18 ft (old scale width)
new scale : 1 in. to 4 ft
length is 9 in.....9 * 4 = 36 ft (new scale length)
width is 6 in......6 * 4 = 24 ft (new scale width)
