I need help please i give brainliest again please

Mathematics

1 answer:

Irina18 [472]3 years ago

5 0

Answer:

Step-by-step explanation:

the reason why it's 36 is because 1.8 is 108 minutes and since she was doing 3 activities we will divide 108 by 3 which equals 36

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A local little league has a total of 90 players of whom 20% are left-handed. How many left-handed players are there? Please help

german

18

First you want to change the 20% into a decimal which is .20
Next you want to multiply 90 by .20 because that will give you the answer for 20% of 90
90x.20=18

Hope that helps

7 0

3 years ago

Our faucet is broken, and a plumber has been called. The arrival time of the plumber is uniformly distributed between 1pm and 7p

Ymorist [56]

Answer:

$E(A+B) = E(A)+E(B)=4+0.5 =4.5 hours$

$Var(A+B)= Var(A)+Var(B)=3+0.25 hours^2=3.25 hours^2$

Step-by-step explanation:

Let A the random variable that represent "The arrival time of the plumber ". And we know that the distribution of A is given by:

$A\sim Uniform(1 ,7)$

And let B the random variable that represent "The time required to fix the broken faucet". And we know the distribution of B, given by:

$B\sim Exp(\lambda=\frac{1}{30 min})$

Supposing that the two times are independent, find the expected value and the variance of the time at which the plumber completes the project.

So we are interested on the expected value of A+B, like this

$E(A +B)$

Since the two random variables are assumed independent, then we have this

$E(A+B) = E(A)+E(B)$

So we can find the individual expected values for each distribution and then we can add it.

For ths uniform distribution the expected value is given by $E(X) =\frac{a+b}{2}$ where X is the random variable, and a,b represent the limits for the distribution. If we apply this for our case we got: