Answer: P(100 ≤ x ≤ 130) = 0.43
Step-by-step explanation:
Since the scores are normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = scores
µ = mean score
σ = standard deviation
From the information given,
µ = 100
σ = 20
We want to find the probability that the scores is between 100 and 130. It is expressed as
P(100 ≤ x ≤ 130)
For x = 100,
z = (100 - 100)/20 = 0
Looking at the normal distribution table, the probability corresponding to the z score is 0.5
For x = 100,
z = (130 - 100)/20 = 1.5
Looking at the normal distribution table, the probability corresponding to the z score is 0.93
Therefore,
P(100 ≤ x ≤ 130) = 0.93 - 0.5 = 0.43
Answer:
the answer is 38.5
Step-by-step explanation:
Answer:
400 sq. ft.
Step-by-step explanation:
We gotta find the length of a side:
First, we divide 80 by 4, because the perimeter of a square is (4 x side):
80 ft. / 4 = 20 ft.
Second, we doing the normal area of a square equation:
= 400 square ft.
Which leads to out answer of 400 sq. ft.
Speed is the ratio of distance and time.
So, average speed= Total distance/ total time.
Let's assume t is the time taken for going from New Orleans to Boston and it's taking 1 hour less to return back. So, time taken for return back is t-1.
Given the speed from New Orleans to Boston is 40 mph. So,
Distance = Speed * time
So, d =40 t
Hence t= d/40
Similarly Distance for returning back:
d =80 (t-1)
d/80 = t-1 (Dividing 80 to each sides)
Now the total distance= d+ d = 2d
And total time : t + t -1= d/40 + d/80
So, the average speed =
= (cancel out d )
Common denominator of 40 and 80 is 80. So, multiply each terms by 80.
=
=
=
=53.33 mph
So, the average speed is 53.33 mph.