Expression equivalent to (0.28t-0.3)-(0.7t-0.28)?

tatuchka [14]

1+8=3r
9=3r
Both divided by 3
3=r

7 0

3 years ago

Use the normal distribution of SAT critical reading scores for which the mean is 502 and the standard deviation is 116. Assume t

PSYCHO15rus [73]

Answer:

(a) 93.19%

(b) 267.3

Step-by-step explanation:

The population mean and standard deviation are given as 502 and 116 respectively.

Consider, X be the random variable that shows the SAT critical reading score is normally distributed.

(a) The percent of the SAT verbal scores are less than 675 can be calculated as:

$P(X$

Thus, the required percentage is 93.19%

(b)

The number of SAT verbal scores that are expected to be greater than 575 can be calculated as:

$P(X>575)=P(\frac{x-502}{116}>\frac{575-502}{116}\\P(X>575)=P(Z>\frac{575-502}{116})\\P(X>575)=P(Z>0.6293)\\P(X>575)=0.2673$

So,

Out of 1000 randomly selected SAT verbal scores, 1000(0.2673) = 267.3 are expected to have greater than 575.

8 0

3 years ago

Ken started a savings account for school. He plans on spending 10% of the money he earns for leisure activities. He needs to hav

uranmaximum [27]

Answer:

$2,400

Step-by-step explanation:

Ken intends to start a savings account

10% = leisure spending

This means 90% = Expenses for school

Let us represent the amount he must save as : x

Hence in other for him to have $2,160 in his savings account, the amount Ken must earn is calculated as:

90/100 × x = $2,160

Cross Multiply

90x = $2,160 × 100

x = ($2,160 × 100) ÷ 90

x =$2,400

Therefore, the amount Ken has to earn to have the amount needed for school is $2,400

5 0

3 years ago

A triangle has a base of x 1/2 m and a height of x 3/4 m. If the area of te triangle is 16m to the power of 2, what are the base

Olenka [21]

Answer:

The base of triangle is $\frac{8}{\sqrt{3}} \ m$ and the height of triangle is $\frac{12}{\sqrt{3}} \ m.$

Step-by-step explanation:

Given:

A triangle has a base of x 1/2 m and a height of x 3/4 m. If the area of the triangle is 16m to the power of 2.

Now, to find the base and height of the triangle.

The base of triangle = $x\times\frac{1}{2} =\frac{x}{2} \ m.$

The height of triangle = $x\times \frac{3}{4} =\frac{3x}{4}\ m.$

The area of triangle = $16\ m^2.$

Now, we put the formula of area to solve:

$Area=\frac{1}{2} \times base\times height$

$16=\frac{1}{2} \times \frac{x}{2} \times \frac{3x}{4}$

$16=\frac{3x^2}{16}$

Multiplying both sides by 16 we get:

$256=3x^2$

Dividing both sides by 3 we get:

$\frac{256}{3} =x^2$

Using square root on both sides we get:

$\frac{16}{\sqrt{3}}=x$

$x=\frac{16}{\sqrt{3}}$

Now, by substituting the value of $x$ to get the base and height:

$Base=\frac{x}{2}\\\\Base=\frac{\frac{16}{\sqrt{3}}}{2} \\\\Base=\frac{8}{\sqrt{3}} \ m.$

So, the base of triangle = $\frac{8}{\sqrt{3}} \ m.$

$Height=x\times\frac{3}{4} \\\\Height=\frac{16}{\sqrt{3}}\times \frac{3}{4} \\\\Height=\frac{12}{\sqrt{3}} \ m.$

Thus, the height of triangle = $\frac{12}{\sqrt{3}} \ m.$

Therefore, the base of triangle is $\frac{8}{\sqrt{3}} \ m$ and the height of triangle is $\frac{12}{\sqrt{3}} \ m.$

7 0

3 years ago

If Martha earns $3.25 per hour for babysitting, how much will she earn in: 1.5 hours? 2.5 hours? 3.5 hours?

IgorC [24]

IF MARTHA EARNS 3.25/HOUR FRO BABYSITTING (SHE IS UNDERPAID!)
IN 1.5 HOURS=3.25*1.5=4.88 DOLLARS
IN 2.5 HOURS=3.25*2.5=8.13 DOLLARS
IN 3.5 HOURS=3.25*3.5=11.38 DOLLARS

6 0

3 years ago

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