I need help solving

Expand the expression by distributing -2(-4x-7)

vova2212 [387]

-2(-4x-7)
Answer:
8x+14

6 0

3 years ago

Terri Vogel, an amateur motorcycle racer, averages 129.71 seconds per 2.5 mile lap (in a 7 lap race) with a standard deviation o

Vikki [24]

Answer:

(a) The percent of her laps that are completed in less than 130 seconds is 55%.

(b) The fastest 3% of her laps are under 125.42 seconds.

(c) The middle 80% of her laps are from 126.80 seconds to 132.63 seconds.

Step-by-step explanation:

The random variable X is defined as the number of seconds for a randomly selected lap.

The random variable X is normally distributed with mean, μ = 129.71 seconds and standard deviation, σ = 2.28 seconds.

Thus, $X\sim N(129.71,\ 2.28^{2})$ .

(a)

Compute the probability that a lap is completes in less than 130 seconds as follows:

$P(X$

$=P(Z$

The percentage is, 0.55 × 100 = 55%.

Thus, the percent of her laps that are completed in less than 130 seconds is 55%.

(b)

Let x represents the 3rd percentile.

That is, P (X < x) = 0.03.

⇒ P (Z < z) = 0.03

The value of z for the above probability is:

z = -1.88

Compute the value of x as follows:

$z=\frac{x-\mu}{\sigma}\\-1.88=\frac{x-129.71}{2.28}\\x=129.71-(1.88\times 2.28)\\x=125.4236\\x\approx 125.42$

Thus, the fastest 3% of her laps are under 125.42 seconds.

(c)

Let x₁ and x₂ be the values between which the middle 80% of the distribution lie.

That is,

$P(x_{1}$

The value of z for the above probability is:

z = 1.28

Compute the values of x₁ and x₂ as follows:

$-z=\frac{x_{1}-\mu}{\sigma}\\-1.28=\frac{x_{1}-129.71}{2.28}\\x_{1}=129.71-(1.28\times 2.28)\\x=126.7916\\x\approx 126.80$ $z=\frac{x_{2}-\mu}{\sigma}\\1.28=\frac{x_{2}-129.71}{2.28}\\x_{2}=129.71+(1.28\times 2.28)\\x=132.6284\\x\approx 132.63$

Thus, the middle 80% of her laps are from 126.80 seconds to 132.63 seconds.

5 0

3 years ago

Ashley can ride her bicycle 15 miles in 2 hours there are 60 minutes I 1 hour and there are 1760 years in 1 mile how many yards

il63 [147K]

Answer:

speed is given by:

speed=distance/time

given that:

1 mile=1,760 yards

1 hour=60 min

then the speed in yards/sec will be:

distance Ashley covered is 15 miles

time=2 hours

thus;

speed=(15x1760)/(2x60)

=220 yards/ min

Step-by-step explanation:

Hi hope helps you :)

5 0

3 years ago

I need help ! It’s says try to analyze it for clues about its purpose and meaning .

Lyrx [107]

Answer:

See explanation

Step-by-step explanation:

The scatter plot shows that there is a negative linear trend. That as the distance to the coffee shop increases, whatever the y value represents goes down.

6 below and 6 above

(1,4) (7,1) Coordinates of the two points on the trend line

I can't see what the Y axis represents so can't really explain the prediction but as the distance to the coffee shop increases, whatever the Y axis represents will decrease.

6 0

2 years ago

Can someone please help me asap with the problem above

GarryVolchara [31]

Do 4.25 divided by 16 witch equals 0.2656625 but you have to round it to 0.27/oz. do 4.55 divided by 20 witch is 0.2275 but you have to round to 0.23/oz now witch is better 0.27 or 0.23 so a 4.55 dollars for a20 oz drink is the better buy

4 0

3 years ago