I need help one all of these questions please help please it due today please

Brittany and Natalie, start cycling together from their home to school, which is 14.4 miles away. Natalie takes 40 minutes to re

prohojiy [21]

Answer:

7.2

Step-by-step explanation:

1. Natalie needed 40 minutes to get to school. In hours 40 minutes is 40/60= 2/3 hour (because there are 60 minutes in an hour). so her speed is 14.4/(2/3)= 14.4*3/2= 21.6 mph.

2. Britany needed 40+20= 60 min. 60 min= 1 hour. so she needed 1 hour her speed is 14,4/1= 14.4mph

3. The difference 21.6-14.4=7.2 is the answer .

3 0

3 years ago

The pH of randomly selected swimming pools follows a normal distribution with mean 7.4 and standard deviation 0.22. A pool shoul

skad [1K]

Answer:

78.383%

Step-by-step explanation:

The pH of randomly selected swimming pools follows a normal distribution with mean 7.4 and standard deviation 0.22. A pool should have a pH between 7.2 and 7.8 so that chlorine treatment is effective.

Using z score formula

z = (x-μ)/σ, where

x is the raw score

μ is the population mean

σ is the population standard deviation.

For x = 7.2

z = 7.2 - 7.4/0.22

z = -0.90909

Probability value from Z-Table:

P(x = 7.2) = 0.18165

For x = 7.8

z = 7.8 - 7.4/0.22

z = 1.81818

Probability alue from Z-Table:

P(x = 7.8) = 0.96548

The probability of pools having an acceptable pH level(7.2 and 7.8)

= P(x = 7.8) - P(x = 7.2)

= 0.96548 - 0.18165

= 0.78383

Converting to percentage

0.78383 × 100

= 78.383%

The percentage of pools having an acceptable pH level is 78.383%

3 0

3 years ago

Can someone please help me with my Question #29 of The Quadratic Relations for me please?

lara [203]

Answer:

Calculate the first differences between the y-values:

$\sf 3 \underset{+1}{\longrightarrow} 4 \underset{+3}{\longrightarrow} 7 \underset{+5}{\longrightarrow} 12 \underset{+7}{\longrightarrow} 19$

As the first differences are not the same, we need to calculate the second differences:

$\sf 1 \underset{+2}{\longrightarrow} 3 \underset{+2}{\longrightarrow} 5 \underset{+2}{\longrightarrow} 7$

As the second differences are the same, the relationship between the variable is quadratic and will contain an $x^2$ term.

--------------------------------------------------------------------------------------------------

To determine the quadratic equation

The coefficient of $x^2$ is always half of the second difference.

As the second difference is 2, and half of 2 is 1, the coefficient of $x^2$ is 1.

The standard form of a quadratic equation is: $y=ax^2+bx+c$

(where a, b and c are constants to be found).

We have already determined that the coefficient of $x^2$ is 1.

Therefore, a = 1

From the given table, when $x=0$ , $y=12$ .

$\implies a(0)^2+b(0)+c=12$

$\implies c=12$

Finally, to find b, substitute the found values of a and c into the equation, then substitute one of the ordered pairs from the given table:

$\begin{aligned}\implies x^2+bx+12 & = y\\ \textsf{at }(1,19) \implies (1)^2+b(1)+12 & = 19\\ 1+b+12 & = 19\\b+13 & =19\\b&=6\end{aligned}$

Therefore, the quadratic equation for the given ordered pairs is:

$y=x^2+6x+12$

7 0

2 years ago

I need help please! Picture below

Anon25 [30]

Answer:

The answer is A

Step-by-step explanation:

A * 2 = 1/2πr^2 * 2

2A / π = πr^2 / π

$\sqrt{\frac{2a}{\pi } }$ = $\sqrt{r^2}$

So, the answer is A because r = $\sqrt{\frac{2a}{\pi } }$

6 0

3 years ago

Read 2 more answers

A coffeepot contains 1 1⁄2 quarts of coffee. After Tonya pours an equal amount of coffee into two cups, 3 1⁄2 cups of coffee rem

PIT_PIT [208]

Answer:

1.25cups(8oz/1cup)=10 ounces

Step-by-step explanation:

we convert 1 1/2 quarts to cups. There are 4 cups in a quart:

1 1/2 quarts= 3/2 quarts (4 cups/ 1 quart)= 6 cups

Amount poured out:

6 cups- 3.5 cups= 2.5 cups

Amount poured in each cup:

2.5/2=1.25 cups

8 0

3 years ago

Read 2 more answers

I need help one all of these questions please help please it due today please​

I need help one all of these questions please help please it due today please