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3 years ago

(3 − 4i)(5 + 2i) A. 15 − 8i B. 23 − 14i C. 15 − 8i2 D. 15 − 14i − 8i2

Mathematics

1 answer:

choli [55]3 years ago

8 0

Answer:

B.23-14i

Step-by-step explanation:

(3x5)+(3x2i)-(4ix5)-(4ix2i)

15+6i-20i-8(-1)

15+6i-20i+8

23-14iฟ

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The result of a subtraction problem is called a quotient. True False

Fynjy0 [20]

Answer:

true

Step-by-step explanation:

7 0

4 years ago

Read 2 more answers

An example problem in a Statistics textbook asked to find the probability of dying when making a skydiving jump.

MArishka [77]

Answer:

(a) 0.999664

(b) 15052

Step-by-step explanation:

From the given data of recent years, there were about 3,000,000 skydiving jumps and 21 of them resulted in deaths.

So, the probability of death is $\frac{21}{3000000}==0.000007$ .

Assuming, this probability holds true for each skydiving and does not change in the present time.

So, as every skydiving is an independent event having a fixed probability of dying and there are only two possibilities, the diver will either die or survive, so, all skydiving can be regarded as is Bernoulli's trial.

Denoting the probability of dying in a single jump by $q$ .

$q=7\times 10^{-6}=0.000007$ .

So, the probability of survive, $p=1-q$

$\Rightarrow p=1-7\times 10^{-6}=0.999993.$

(a) The total number of jump he made, n=48

Using Bernoulli's equation, the probability of surviving in exactly 48 jumps (r=48) out of 48 jumps (n=48) is

$=\binom(n,r)p^rq^{n-r}$

$=\binom(48,48)(0.999993)^{48}(0.000007)^{48-48}$

$=(0.999993)^{48}=0.999664$ (approx)

So, the probability of survive in 48 skydiving is 0.999664,

(b) The given probability of surviving =90%=0.9

Let, total $n$ skydiving jumps required to meet the surviving probability of 0.9.

So, By using Bernoulli's equation,

$0.9=\binom {n }{r} p^rq^{n-r}$

Here, r=n.

$\Rightarrow 0.9=\binom{n}{n}p^nq^{n-n}$

$\Rightarrow 0.9=p^n$

$\Rightarrow 0.9=(0.999993)^n$

$\Rightarrow \ln(0.9)=n\ln(0.999993)$ [ taking $\log_e$ both sides]

$\Rightarrow n=\frac {\ln(0.9)}{\ln(0.999993)}$

$\Rightarrow n=15051.45$

The number of diving cant be a fractional value, so bound it to the upper integral value.

Hence, the total number of skydiving required to meet the 90% probability of surviving is 15052.

3 0

3 years ago

Robert believes that the lengths 8 in, 13 in, and 20 in will form a triangle. Is he correct?

adell [148]

Answer: I think it’s D

Step-by-step explanation:

it’s because 8^2 + 13^2 equals 233 and when square rooted equals 15.26 not 20 so no.

7 0

3 years ago

If an ambulance has an average speed of 0.83 miles per minute and an average response time of 8 minutes, what is the average dis

Mrac [35]

Answer: The average distance the ambulance travels to reach an emergency situation is 6.64 miles.

Step-by-step explanation:

Hi, to answer this question we have to apply the speed formula:

Speed rate = distance / time

Replacing with the values given:

0.83 miles per minute = d / 8 minutes

Solving for d (distance)

0.83 mpm x 8 m =d

d =6.64 miles

The average distance the ambulance travels to reach an emergency situation is 6.64 miles.

Feel free to ask for more if needed or if you did not understand something.

4 0

3 years ago

Consider the following expression and determine which statements are true.

Serhud [2]

Given:

$$\frac{7}{r}+2^{3}+\frac{s}{3}+11$

To find:

Which statement are true?

Solution:

Option A: The entire expression is a sum.

It is true because it performed addition operation.

Option B: The coefficient of s is 3.

$$\frac{7}{r}+2^{3}+\frac{s}{3}+11=\frac{7}{r}+2^{3}+\frac{1}{3}s+11$

It is not true because the coefficient of s is $\frac{1}{3}$ .

Option C: The term $\frac{7}{r}$ is a quotient.

If we divide 7 by r, we obtain a quotient.

So it is true.

Option D: The term $2^3$ has a variable.

It is not true because it does not contain any variable.

Therefore the entire expression is a sum and the term $\frac{7}{r}$ is a quotient are true statement.

3 0

3 years ago