9x squared -25 a difference of squares

Andrew jogs for 3 miles each day on the weekdays and for 6.5 miles each day over the weekend. What is the average distance that

kirill [66]

Set up the data:
3,3,3,3,3,6.5,6.5
15+13=28
28/7=4

He runs an average of 4 miles a day

7 0

3 years ago

Read 2 more answers

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

Six machines, each working at the same constant rate, together can complete a certain job in 12 days. How many additional machin

Schach [20]

Answer:

3 machine

Step-by-step explanation:

It is given that 6 machine each working at the same rate can complete the work in 12 days

We the has to complete in 8 days

Let we need x extra machine to complete the work in 8 days

So total number of machines =x+6

Now according to man work day equation $M_1D_1=M_2D_2$

$6\times 12=(x+6)\times 8$

$8x+48=72$

$8x=24$

x=3 machine

7 0

3 years ago

What is the unit ratio for a button of 16 grams and 2 milliliters?

Reika [66]

Answer:

The unit ratio would be 8 grams per milliliters

Step-by-step explanation:

Since, the unit ratio is a fraction with denominator 1,

In other words, the amount of one quantity in unit amount of other quantity is called unit rate or unit ratio.

Here, the amount first quantity = 16 grams,

The amount of second quantity = 2 milliliters,

Thus, unit ratio = $\frac{\text{First quantity}}{\text{Second quantity }}$

$=\frac{16}{2}$ = 8 grams per milliliters

6 0

2 years ago

Jay estimates that a basketball weights about .5 pounds. Shawna estimates that a basketball weights about.05. Whose estimate is

Natasha_Volkova [10]

Answer:

Jay's estimate is closer to the actual weight of the basketball

Step-by-step explanation:

The standard weight of an NBA basketball is 1.4 pounds.

Judging the accuracy of Jay's and Shawna's answer based on their percentage error when compared with the standard, we have that Jay's answer has a lower error as shown below

Error = (Standard value - Estimated value)/ Standard Value ×100

Error in Jays answer = $\frac{1.4 - 0.5}{1.4}$ × 100 = 64.28 %

Error in Shawna's answer = $\frac{1.4 - 0.05}{1.4}$ × 100 = 96.42%

From this, It is obvious that Jay's answer has a lower percentage error when compared to the actual value.

8 0

2 years ago