Please help me me me

In a recent year, a sample of grade 8 Washington State public school students taking a mathematics assessment test had a mean sc

Daniel [21]

Answer:

The number is $N =1147$ students

Step-by-step explanation:

From the question we are told that

The population mean is $\mu = 281$

The standard deviation is $\sigma = 34.4$

The sample size is n = 2000

percentage of the would you expect to have a score between 250 and 305 is mathematically represented as

$P(250 < X < 305 ) = P(\frac{ 250 - 281}{34.4 } < \frac{X - \mu }{\sigma } < \frac{ 305 - 281}{34.4 } )$

Generally

$\frac{X - \mu }{\sigma } = Z (Standardized \ value \ of \ X )$

So

$P(250 < X < 305 ) = P(-0.9012< Z$

$P(250 < X < 305 ) = P(z_2 < 0.698 ) - P(z_1 < -0.9012)$

From the z table the value of $P( z_2 < 0.698) = 0.75741$

and $P(z_1 < -0.9012) = 0.18374$

$P(250 < X < 305 ) = 0.75741 - 0.18374$

$P(250 < X < 305 ) = 0.57$

The percentage is $P(250 < X < 305 ) = 57\%$

The number of students that will get this score is

$N = 2000 * 0.57$

$N =1147$

6 0

3 years ago

Which square root is a whole number? A) 222 B) 223 C) 224 D) 225

zepelin [54]

225, the square root of 225 is 15

3 0

3 years ago

Read 2 more answers

Help. Solving Multi Step Ratio Problems!

Romashka-Z-Leto [24]

Answer:

Part 1) $30\ coupons$

Part 2) $12\ sandwiches$

Part 3) $60\ push-ups$

Part 4) $96\ minutes$

Part 5) $\$95$

Part 6) $1\frac{7}{8}\ cups\ of\ pretzel$

Step-by-step explanation:

Part 1) we know that

At the Green House of Salad , you get a $1 coupon for every 3 salads you buy

so

Using proportion

Find out the number of salads you could buy to get $10 in coupons

$\frac{1}{3}=\frac{10}{x} \\\\x=3(10)\\\\x=30\ coupons$

Part 2) we know that

Kim orders catering for $35

She spend $5 on a large order of potato salad and the rest on turkey sandwiches

Each sandwich is $2.50

How many sandwiches does Kim buy?

step 1

Find out how many Kim spent on turkey sandwiches

Subtract $5 from $35

35-5=$30

step 2

Using proportion, find out the number of sandwiches

so

$\frac{1}{2.50}=\frac{x}{30}\\\\x=30/2.50\\\\x= 12\ sandwiches$

Part 3) we know that

Molly does 10 push-ups at the same time as Liza does 15 push-ups

so

Using proportion

Find out how many push-ups Liza does when Molly does 40 push-ups

$\frac{10}{15}=\frac{40}{x}\\\\x=15(40)/10\\\\x=60\ push-ups$

Part 4) we know that

A shark swim at a speed of 25 miles per hour

The shark rest after 40 miles

How long in minutes, does the shark swim before resting?

Using proportion

Find out how long in minutes the shark swim 40 miles

Remember that

$1\ h=60\ min$

$\frac{25}{60}\ \frac{miles}{minutes}=\frac{40}{x}\ \frac{miles}{minutes}\\\\x=60(40)/25\\\\x=96\ minutes$

Part 5) we know that

For every bar of soap that Aly sells, she earns $5

For every mug that Janet sells, she earns twice as much as Aly

Aly sells 5 bars of soap and Janet sells 7 mugs

How much money did they make altogether?

step 1

Find out the amount earned by Aly

using proportion

$\frac{1}{5}=\frac{5}{x}\\\\x=5(5)\\\\x=\$25$

step 2

Find out the amount earned by Janet

Remember that

For every mug that Janet sells, she earns twice as much as Aly

so

For every mug that Janet sells, she earns 2($5)=$10

using proportion

$\frac{1}{10}=\frac{7}{x}\\\\x=10(7)\\\\x=\$70$

step 3

Adds the amount earned by Aly plus the amount earned by Janet

$25+70=\$95$

Part 6) we know that

Ted is making trail mix for a party

He mixes 1 1/2 cups of nuts, 1/4 cup of rising and 1/4 cup of pretzel

How many cups of pretzel does Ted need to make 15 cups of trail mix?

Adds the quantities

$1\frac{1}{2}+\frac{1}{4} +\frac{1}{4}=2\ cups\ of \ trail\ mix$

That means

For every 2 cups of trail mix we need 1/4 cup of pretzel

using proportion

Find out how many cups of pretzel does Ted need to make 15 cups of trail mix

$\frac{2}{(1/4)}=\frac{15}{x}\\\\x=15(1/4)/2\\\\x=\frac{15}{8}\ cups\ of\ pretzel$

Convert to mixed number

$\frac{15}{8}=\frac{8}{8}+\frac{7}{8}=1\frac{7}{8}\ cups\ of\ pretzel$

6 0

3 years ago

For every 3 laps that Jackie swims, Ronnie swims 4 laps. During practice, they swam a combined total of 63 laps. How many laps d

Flura [38]

Answer:

36 laps Ronnie swim during practice .

Step-by-step explanation:

Let us assume that the laps that Ronnie swims be x .

Let us assume that the laps that Jackie swims be y .

As given

For every 3 laps that Jackie swims, Ronnie swims 4 laps.

i.e

3 × laps that Ronnie swims = 4 × laps that Jackie swims

3 × x = 4 × y

3x = 4y

Equation becomes

x + y = 63

Thus by using 3x = 4y .

$y = \frac{3x}{4}$

Thus

$x +\frac{3x}{4} = 63$

4x + 3x = 63 × 4

7x = 252

x = 36

Put the value of x in the equation x + y = 63

36 + y = 63

y = 63 - 36

y = 27

Therefore the 36 laps Ronnie swim during practice .

4 0

2 years ago

Which word is used to name the bold number?

yuradex [85]

The bold number (10) is the difference because it is calculated by subtracting two numbers.

3 0

2 years ago