We have such system of eq
First lets solve second eq
7x=21 /:7 divide both sides by 7
x=3
Now we can substitute it to first equation
9x-2y=19
9*3-2y=19
27-2y=19 /-27 subtract 27 both sides
-2y=-8 /:(-2) divide both sides by -2
y=4 - its the answer
Answer:
The answer to your question is letter c and d.
Step-by-step explanation:
A. 15 × 9 = 135 and 135 – 75 = 60 This answer is not correct because it is not necessary to multiply the # members by the cost of each tree, the answer is incorrect.
B. 3 × 15 = 45 and 45 + 15 = 60 This answer is incorrect because it's using a number 3 that is not part of the data.
C. 45 ÷ 9 = 5 and 5 × 15 = 75
. This answer is correct, first finds the number of tree bought by each member and after that multiply it by the cost of each tree.
D. 45 × 15 = 675 and 675 ÷ 9 = 75 This answer is correct, first found the total cost and after divide it by the number of members.
Answer: the sample size should be 39
Step-by-step explanation:
The sample mean is the point estimate for the population mean. Confidence interval is written as
Sample mean ± margin of error
Margin of error = z × σ/√n
Where
σ = population standard Deviation
n = number of samples
z represents the z score corresponding to the confidence level
From the information given,
σ = 4 minutes
Margin of error = 75 seconds. Converting to minutes, it becomes 75/60 = 1.25 minutes
To determine the z score, we subtract the confidence level from 100% to get α
α = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
This is the area in each tail. Since we want the area in the middle, it becomes
1 - 0.025 = 0.975
The z score corresponding to the area on the z table is 1.96. Thus, confidence level of 95% is 1.96
Therefore,
1.25 = 1.96 × 4/√n
1.25/1.96 = 4/√n
0.6378 = 4/√n
√n = 4/0.6378 = 6.27
n = 6.27² = 39
Begin by following the herd . . . call the two numbers 'x' and 'y' .
You said that xy=1 , so y = 1/x
You said that x + y = 10, so x + 1/x = 10
Multiply each side by 'x': x² + 1 = 10x
Subtract 10x from each side: x² - 10x + 1 = 0
Use the quadratic formula to solve this, and the two solutions
that you get for 'x' are also the two numbers 'x' and 'y' .
They are
<em>9.89898</em>
and
<em>0.10102</em>
(rounded)
