Since Emily is walking at a constant speed, we can solve this using proportions, equating ratios of distance/time.
The first ratio is 3/4 miles/1/4 hour
The second ratio is 1 mile/ x hour
Equating the two ratios: 3/4 / 1/4 = 1/x
3 = 1/x
x = 1/3 hour
Answer:
The probability is 0.003
Step-by-step explanation:
We know that the average
is:

The standard deviation
is:

The Z-score is:

We seek to find

For P(x>800) The Z-score is:



The score of Z = 3 means that 800 is 3 standard deviations from the mean. Then by the rule of the 8 parts of the normal curve, the area that satisfies the conficion of 3 deviations from the mean has percentage of 0.15%
So

For P(x<200) The Z-score is:



The score of Z = -3 means that 200 is 3 standard deviations from the mean. Then by the rule of the 8 parts of the normal curve, the area that satisfies the conficion of 3 deviations from the mean has percentage of 0.15%
So

Therefore



Step-by-step explanation:
there must be something wrong with your text.
what we can see is
3.8 × 105
and
1.9 × 1022
the true answer for these values has nothing to do with the 4 answer options.
maybe you meant
1.9 × 10.5 ?
because that answer would be 20.
but first working with the presented numbers :
3.8 × 105 = 399
1.9 × 1022 = 1941.8
so, the second number is actually much bigger than the first number.
but if it is
1.9 × 10.5 = 19.95
that works.
and we can either use the calculator to calculate
399 / 19.95 = 20
or we can simply look at the factor changes of the multiplication terms.
3.8 = 1.9 × 2
105 = 10.5 × 10
so, the multiplication product of the two larger numbers is then 2×10=20 times larger than the product of the 2 smaller numbers.
The answer is B because you must multiply 135 by 9 to get the answer of the tree