Answer:
11.45 lumens
Step-by-step explanation:
We are given that

Where x=Depth
I=Intensity of light
We have to find the intensity of the light at a depth of 20 feet.
Substitute the value of x





Hence, the intensity of the light (in lumens) at a depth of 20 feet=11.45 lumens
Answer:
Therefore the probability that a pen from the first box and a crayon from the second box are selected is 
Step-by-step explanation:
Probability:
The ratio of the number of favorable outcomes to the number all possible outcomes of the event.

Given that,
Three plain pencils and 5 pens are contained by the first box.
Total number of pens and pencils is =(3+5)=8
The probability that a pen is selected from the first box is
=P(A)


A second box contains three colored pencils and three crayons.
Total number of pencils and crayons is =(3+3)=6
The probability that a crayon is selected from the second box is
=P(B)


Since both events are mutually independent.
The required probability is multiple of the events
Therefore the required probability is


Answer:
A. The distribution of sample means of the differences will be approximately normal if there are at least 30 years of data in the sample and/or if the population of differences in winning times for all years is normal.
Step-by-step explanation:
In other to perform a valid paired test, one of the conditions required is that, data for both groups must be approximately normal. To attain normality, the population distribution for the groups must be normal or based on the central limit theorem, the sample size must be large enough, usually n > 30. Hence, once either of the two conditions are met, the paired sample will be valid.
D+Q=61 => D=61-Q
3+D=Q
10D+25Q=1090
10(61-Q) + 25Q=1090
610-10Q+25Q=1090
610+15Q=1090
-610 -610
15Q=480
480/15=32
32 quarters