Answer:
Step-by-step explanation:
2
(
2
x
−
1
)
+
7
<
13
Expand LHS
→
4
x
−
2
+
7
<
13
4
x
+
5
<
13
4
x
<
13
−
5
4
x
<
8
Divide through by
4
→
x
<
2
x
<
2
is represented on the real line by the interval
(
−
∞
,
2
)
This can be represented on the
x
y
−
plane by the area to the left of the vertical line
x
=
2
as graph below.
graph{2(2x-1)+7<13 [-10, 10, -5, 5]}
Short Answer: 18 minutes
Remark
The answer to this problem is less than the smallest time of the two people working together. that fact lets out C and D (38 minutes and 75 minutes). Now you have to choose 15 minutes and 18 minutes. There's a method. No guessing needed.
Givens
Let the time for Sophie = S
Let the time for Simon = M
Let the job to completion = 1
S = 45 minutes
M = 30 minutes
Step One
Convert minutes to hours.
45 minutes = 45 / 60 = 3/4 hour = 0.75 hour
30 minutes = 30 / 60 = 1/2 hour = 0.50 hour
Step Two
Set up the Equation
The formula is a form of job / hour.
Let the time = t that they both have to work
job = 1 in these problems.
1/S + 1/M = 1/t
1/0.75 + 1/0.5 = 1/t
Solve
1 ÷ 0.75 = 1.33333
1 ÷ 0.5 = 2
1.3333 + 2 = 3.33333
3.3333 = 1 / t Multlply both sides by t
3.3333*t = 1
t = 1 / 3.333333333
t = 0.3 of an hour
1 hour = 60 minutes
0.3 hours = x Cross Multiply
x = 60 * 0.3
x = 18 minutes
Answer working together it took them 18 minutes <<<<<
Answer:
i think the anwser is the third one c
Answer:
Due to the higher z-score, he did better on the SAT.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean 
and standard deviation 
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Determine which test the student did better on.
He did better on whichever test he had the higher z-score.
SAT:
Scored 1070, so 
SAT scores have a mean of 950 and a standard deviation of 155. This means that 
.
ACT:
Scored 25, so 
ACT scores have a mean of 22 and a standard deviation of 4. This means that 
Due to the higher z-score, he did better on the SAT.
