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3 years ago

Is -7 + 9= 9 + 7 true, false or open

2 answers:

6 0

$-7 + 9 \neq 9 + 7$

$2 \neq 17$

When you add a positive number and a negative number, you get a positive, but the number is smaller. If you add two positive numbers, then of course, you're going to get a positive number as an answer. But overall, this is false.

True [87]3 years ago

5 0

That's false -7+9=2 and 7+9=18

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Suppose N has a geometric distribution with parameter p. Derive a closed-form expression for E(N | N <= k), k = 1,2,... Check

vfiekz [6]

Answer:

P(X= k) = (1-p)^k-1.p

Step-by-step explanation:

Given that the number of trials is

N < = k, the geometric distribution gives the probability that there are k-1 trials that result in failure(F) before the success(S) at the kth trials.

Given p = success,

1 - p = failure

Hence the distribution is described as: Pr ( FFFF.....FS)

Pr(X= k) = (1-p)(1-p)(1-p)....(1-p)p

Pr((X=k) = (1 - p)^ (k-1) .p

Since N<=k

Pr (X =k) = p(1-p)^k-1, k= 1,2,...k

0, elsewhere

If the probability is defined for Y, the number of failure before a success

Pr (Y= k) = p(1-p)^y......k= 0,1,2,3

0, elsewhere.

Given p= 0.2, k= 3,

P(X= 3) =( 0.2) × (1 - 0.2)²

P(X=3) = 0.128

3 0

3 years ago

A rectangle has a perimeter of 52 cm and an area of 144 square cm. Find its length and width if they are in whole numbers.

Bingel [31]

8 and 18:
8+8+18+18= 52
$8*18$ = 144

Tada!

6 0

3 years ago

What is 7.04 trillion in scientific notation

slega [8]

Answer:

7.04 trillion = 7.04 x 10¹²

Step-by-step explanation:

4 0

3 years ago

If w = -2 and v = -8, which of the following expressions shows the values correctly substituted in for the variables in the expr

ki77a [65]

Answer:

the first one

(-2) 2-(-8)+1

3 0

3 years ago

Read 2 more answers

A scientist running an experiment starts with 100 bacteria cells. These bacteria double their population every 15 hours. Find ho

IRISSAK [1]

<h2>Hello!</h2>

The answer is: 23.77 hours

$Total(t)=Start*2^\frac{t}{15}$

Where:

Total(t) is equal to the amount for a determined time (in hours)

<em>Start</em> is the original amount

<em>t </em>is the time in hours.

For example, it's known from the statement that the bacteria double their population every 15 hours, so it can be written like this:

$Total(15)=100*2^\frac{15}{15}=100*2^{1}=100*2=200$

To calculate how long it takes for the bacteria cells to increase to 300, we should do the following calculation:

$300=100*2^{\frac{t}{15} } } \\\frac{300}{100}=2^{\frac{t}{15} } }\\log(3)=log(2^{\frac{t}{15} })\\\\\\log(3)=\frac{t}{15}*log2\\t=\frac{log(3)}{log(2)} *15=23.77$

So, to know if we are right, let's replace 23.77 h in the equation:

Total(t)=100*2^\frac{23.77}{15}=299.94

and 299.94≅300

Have a nice day!

8 0

3 years ago

Read 2 more answers