The total number of cars both the student and the teacher made is 49
let
total cars = x
cars made by student = s
cars made by teacher = t
Total = student + teacher
x = s + t
s = 2/7x
So,
x = 2/7x + t
x - 2/7x = t
t = (7x - 2x) / 7
t = 5/7x
Similarly,
s = t - 21
s = 5/7x - 21
equate both s equation
2/7x = 5/7x - 21
2/7x - 5/7x = -21
(2x - 5x) / 7 = -21
- 3/7x = -21
x = -21 ÷ -3/7
= -21 × - 7/3
= (-21 × -7) / 3
= 147/3
x = 49
Therefore, the total number of cars both the student and the teacher made is 49
Learn more about fractions:
brainly.com/question/11562149
In the International System of Units (SI), the unit of power is the watt (W), which is equal to one joule per second.
SI unit: watt (W)
In SI base units: kg⋅m2⋅s−3
Answer:
The middle 90% of all freshman biology majors' GPAs lie between 2.31 and 3.43.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.
Mean 2.87 and standard deviation .34.
This means that
Middle 90% of scores:
Between the 50 - (90/2) = 5th percentile and the 50 + (90/2) = 95th percentile.
5th percentile:
X when Z has a pvalue of 0.05. So X when Z = -1.645.
95th percentile:
X when Z has a pvalue of 0.95. So X when Z = 1.645.
The middle 90% of all freshman biology majors' GPAs lie between 2.31 and 3.43.
Answer:
Step-by-step explanation:
Distribute :
Distribute :
Simplify:
Final Answer: