Round 2.408 to the nearest hundredth

The average income, I, in dollars, of a lawyer with an age of x years is modeled with the following function:

Alinara [238K]

The answer is 37 years old.

I = -425x² + 45500x -650000
I = 450000

-425x² + 45500x -650000 = 450000
-425x² + 45500x - 650000 - 450000 = 0
-425x² + 45500x - 1100000 = 0

Divide all factors by 25:
- 17x² + 1820x - 44000 = 0

This is quadratic equation (ax² + bx + c = 0)
$x_{1,2} = \frac{-b+/- \sqrt{ b^{2}-4ac } }{2a} = \frac{-1820+/- \sqrt{ 1820^{2}-4*(-17)*(-44000) } }{2*(-17)} = \\ \\ = \frac{-1820+/- \sqrt{3312400-2992000 } }{-34} = \frac{-1820+/- \sqrt{320400} }{-34} =\frac{-1820+/- 566}{-34} \\ \\ 
x_1= \frac{-1820+ 566}{-34}= -37 \\ \\ 
x_2 = \frac{-1820- 566}{-34}=70$

Since, the youngest age is needed, the correct answer is x = 37

3 0

3 years ago

Two girls scout troops are completing a wilderness campout. Use the information to answer the questions. The Blue Tripp hikes 2/

Nikitich [7]

Answer:

Kindly check explanation

Step-by-step explanation:

Given the following :

Blue tripp:

Hikes 2/3 miles every 1/2 hour

Yellow troop:

Hikes 3/4 miles every 1/3 hour

How long does it take each troop to walk 1 1/2 miles, 1/2 mile, and 3/4 mile?

To hike 1 1/2 miles

Blue troop:

2/3 miles = 1/2 hours

3/2 miles = x

2/3x = 3/4

x = 3/4 * 3/2

x = 9/8 = 1 1/8 hours

Yellow troop:

3/4 = 1/3 hours

3/2 = x

3/4x = 3/6

x = 3/6 * 4/3

x = 12/18 = 2/3 hours

To hike 1/2 mile :

Blue troop:

2/3 miles = 1/2 hours

1/2 miles = x

2/3x = 1/4

x = 1/4 * 3/2

x = 3/8 hours

Yellow troop:

3/4 = 1/3 hours

1/2 = x

3/4x = 1/6

x = 1/6 * 4/3

x = 4/18 = 2/9 hours

To hike 3/4 miles :

Blue troop:

2/3 miles = 1/2 hours

3/4 miles = x

2/3x = 3/8

x = 3/8 * 3/2

x = 9/16 hours

Yellow troop:

3/4 = 1/3 hours

3/4 = x

3/4x = 3/12

x = 1/4 * 4/3

x = 4/12

x = 1/3 hours

4 0

3 years ago

A survey showed that students were 2:3 in favour of the new team logo. In all, 780 people were surveyed, how many were in favour

defon

468 students were in favour of the new logo

4 0

3 years ago

Read 2 more answers

Alison, the owner of a regional chain of pizza stores, is trying to decide whether to add calzones to the menu. She conducts a s

Mekhanik [1.2K]

Answer:

Step-by-step explanation:

Confidence interval is written as

Sample proportion ± margin of error

Margin of error = z × √pq/n

Where

z represents the z score corresponding to the confidence level

p = sample proportion. It also means probability of success

q = probability of failure

q = 1 - p

p = x/n

Where

n represents the number of samples

x represents the number of success

From the information given,

n = 700

x = 46

p = 46/700 = 0.066

q = 1 - 0.066 = 0.934

To determine the z score, we subtract the confidence level from 100% to get α

α = 1 - 0.9 = 0.1

α/2 = 0.1/2 = 0.05

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.05 = 0.95

The z score corresponding to the area on the z table is 1.645. Thus, the z score for a confidence level of 90% is 1.645

Therefore, the 90% confidence interval is

0.066 ± 1.645√(0.066)(0.934)/700

= 0.066 ± 0.0094

The lower limit of the confidence interval is

0.066 - 0.0094 = 0.0566

The upper limit of the confidence interval is

0.066 + 0.0094 = 0.0754

5 0

3 years ago

There are 10 boys and 20 girls in Mrs Brook's class.

notsponge [240]

Answer:

Step-by-step explanation:

First let us consider how we calculate the mean test mark in the first place, we add up the individual test marks of the entire class to give the total test mark then we divide by the number of students. This means we need two pieces of information to calculate the boys' mean mark, the total boys' mark and the number of boys. We already know the number of boys but how do we work out the total boys' test mark? If we can work out the total class mark and total girls' mark we can find the total boys' mark by subtracting the total girls' mark from the total class mark. To do this we can work backwards to find the total mark for the whole class by taking the mean mark and multiplying it by the number of students, this gives us Total Class Mark = Mean Class Mark x Number of Students = 60 x 30 = 1800. We can do the same for the girls' mark giving us Total Girls' Mark = Mean Girls' Mark x Number of Girls = 54 x 20 = 1080. This then gives us the total boys mark as Total Boys' Mark = Total Class Mark - Total Girls' Mark = 1800 - 1080 = 720. Now we have everything we need to work out the boys' mean mark and we get Boys' Mean Mark = Total Boys' Mark/Number of Boys = 720/10 = 72.

4 0

3 years ago