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2 years ago

9

A ball is thrown upwards and it’s height h m,at time t s,is given by h=7t-4.9t2.How long does the ball spend more than 1.5m abov

e ground?

1 answer:

Allushta [10]2 years ago

4 0

Answer: From what you wrote the I think the ball is drop

At time 0 you are 7 meters above ground

You basically just need to solve for

1.5 =7t-4.9t^2

by rearrange the equation you get

4.9t^2-7t+1.5=0

by using Quadratic Formula

t=1.166s

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Underage drinking, Part II: We learned in Exercise 3.25 that about 69.7% of 18-20 year olds consumed alcoholic beverages in 2008

Murrr4er [49]

Answer:

Step-by-step explanation:

Hello!

The variable of interest is

X: number of 18-20-year-olds that consume alcoholic beverages in a sample of 50.

The proportion of underage people that drinks are known to be p= 0.697

This variable is discrete. This experiment has two possible outcomes success or failure, we will call "success" each time we encounter an underage individual that consumes alcohol and "failure" will be counting an underage that does not consume alcohol. The number of repetitions of the trial is fixed n= 50. All randomly selected underage individuals are independent and the probability of success is constant trough the whole experiment p=0.697.

Then we can say that this variable has a binomial distribution and we will use that distribution to do the calculations.

a. Under a binomial distribution, the expected value is calculated as:

E(X)= n*p= 50*0.697= 34.85.

The variance of a binomial distribution is:

V(X)= n*p*(1-p)= 50*0.697*0.303= 10.55955

And the standard deviation is the square root of the variance:

√V(X)= 3.2495 ≅ 3.25

b. To know how rare the value 45, you have to see how distant it is concerning the expected value. For this you have to subtract the expected value and divide it by the standard deviation:

[X-E(X)]/√V(X)

(45-34.85)/3.25= 3.12

The value X=45 is 3.12 standard deviations above the mean, which means that it would be rare to find 45 people or more than consumed alcohol.

c. P(X≥45) = 1 - P(X<45)= 1 - P(X≤44)= 1 - 0.9994= 0.0006

I hope it helps!

8 0

2 years ago

On monday maggie ran n miles on tuesday she ran 90% of the number of miles she ran on monday and on tuesday she ran 50% of the n

kari74 [83]

Answer:

let number of mile on monday be x

tuesday = 9/10 of x

wednesday = 9/20 of x

Step-by-step explanation:

tues = 90/100=9/10

wednes = 50/100 * 90/100 * x

wednes = 9/20 of x

3 0

2 years ago

An online furniture store sells chairs for $200 each and tables for $600 each. Every day, the store can ship a maximum of 32 pie

wolverine [178]

Answer:

If the minimum 13 chair were sold , then the minimum number of Table sold is 14

Step-by-step explanation:

Given as :

The cost of each chair = $ 200

The cost of each table = $ 600

The total number of furniture sold per day = 32

The minimum amount of selling per day = $ 12000

Let the total number of chair = C

The total number of table = T

So , according to question

C + T = 32 .......1

200 C + 600 T = 12000 .......2

Solving eq 1 and 2

200 C + 600 T = 12000

200 × ( C + T ) = 32 × 200

I.e 200 C + 200 T = 6400

or, ( 200 C + 600 T ) - ( 200 C + 200 T ) = 12,000 - 6400

Or, 400 T = 5600

∴ T = $\frac{5600}{400}$

I.e T = 14

Put The value of T in eq 2

So, 200 C + 600 × 14 = 12000

or , 200 C + 8400 = 12,000

Or, 200 C = 12000 - 8400

Or, 200 C = 3600

∴ C = $\frac{3600}{200}$

I.e C = 18

The number of chair sold is 18

If the number of chair sold is 13 ,

Then the min number of table sold = 200 × 18 + 600 T = 12000

i.e 600 T = 12000 - 3600

or, 600 T = 8400

∴ T = $\frac{8400}{600}$

I.e T = 14

Hence if the minimum 13 chair were sold , then the minimum number of Table sold is 14 . Answer

5 0

2 years ago

g A car company is testing a new type of tire. They want to determine the stopping distance if the car has anti-lock brakes or n

Keith_Richards [23]

Answer:

Road conditions

Step-by-step explanation:

The factor that should be mostly considered in this case is the Road conditions, that way the tyre with the best stopping distance can be determined.

6 0

2 years ago

The slope of diagonal OA is ? and its equation is ?

Nimfa-mama [501]

Answer:

Slope = $\frac{4}{3}$

Equation of the line → $y=\frac{4}{3}x$

Step-by-step explanation:

Let the equation of diagonal OA is,

y = mx + b

Here, m = Slope of the line OA

b = y-intercept

Slope of a line passing through two points $(x_1,y_1)$ and $(x_2,y_2)$ is given by,

m = $\frac{y_2-y_1}{x_2-x_1}$

Therefore, slope of the line passing through O(0, 0) and A(3, 4) will be,

m = $\frac{4-0}{3-0}$

m = $\frac{4}{3}$

Since, line OA is passing through the origin, y-intercept will be 0.

Therefore, equation of OA will be,

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

3 0

2 years ago