All categories

2 years ago

Micha washed a car in 20 minutes. At this rate, how many hours would it take to wash 9 cars?

Mathematics

1 answer:

blsea [12.9K]2 years ago

5 0

Answer:

3 hours

Step-by-step explanation:

he washed one car in 20 minutes so 9 cars will be 20 x 9=180minutes which is 3 hours

You might be interested in

f) The life of a power transmission tower is exponentially distributed, with mean life 25 years. If three towers, operated indep

Step2247 [10]

Answer:

15.24% probability that at least 2 will still stand after 35 years

Step-by-step explanation:

To solve this question, we need to understand the binomial distribution and the exponential distribution.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

Probability of a single tower being standing after 35 years:

Single tower, so exponential.

Mean of 25 years, so $m = 25, \mu = \frac{1}{25} = 0.04$

We have to find $P(X > 35)$

$P(X > 35) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-0.04*35} = 0.2466$

What is the probability that at least 2 will still stand after 35 years?

Now binomial.

Each tower has a 0.2466 probability of being standing after 35 years, so $p = 0.2466$

3 towers, so $n = 3$

We have to find:

$P(X \geq 2) = P(X = 2) + P(X = 3)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 2) = C_{3,2}.(0.2466)^{2}.(0.7534)^{1} = 0.1374$

$P(X = 3) = C_{3,3}.(0.2466)^{3}.(0.7534)^{0} = 0.0150$

$P(X \geq 2) = P(X = 2) + P(X = 3) = 0.1374 + 0.0150 = 0.1524$

15.24% probability that at least 2 will still stand after 35 years

4 0

2 years ago

Which lists all of the y-intercepts of the continuous

8090 [49]

Answer: (0,0)

Step-by-step explanation:

got it correct

5 0

2 years ago

What is the surface area of the prism in square inches?

Kay [80]

<u>Given</u>:

Given that the triangular prism with height 10 inches.

The side lengths of the base of the triangle are 12 inches, 13 inches and 5 inches.

We need to determine the surface area of the prism.

<u>Surface area of the prism:</u>

The surface area of the prism can be determined using the formula,

$SA=bh+(s_1+s_2+s_3)H$

where b is the base and h is the height of the triangle.

s₁, s₂, s₃ are the side lengths of the triangle and

H is the height of the prism.

Substituting b = 12, h = 5, s₁ = 12, s₂ = 5, s₃ = 13 and H = 10 in the above formula, we get;

$SA=(12)(5)+(12+5+13)(10)$

$SA=60+(30)(10)$

$SA=60+300$

$SA=360 \ in^2$

Thus, the surface area of the triangular prism is 360 square inches.

Hence, Option b is the correct answer.

8 0

3 years ago

Sets M and F are defined as follows.

a_sh-v [17]

Answer:

intersection is /c,d/

Step-by-step explanation:

circle the common members and list them

6 0

2 years ago

The table below shows the hourly temperatures, for a city in Ohio on February 10, 2012, as predicted by the weatherman at the lo

bekas [8.4K]

Answer:

Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool.

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers