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2 years ago

Four times the reciprocal of a number equal 2 times the reciprocal of 8

Mathematics

1 answer:

garik1379 [7]2 years ago

5 0

Answer:

Step-by-step explanation:

Let the number be y & reciprocal simply means inverse of the number

4×1/y=2×1/8 solving for y

4/y=2/8; y = 16

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There are 4 teams in a basketball league. Each team plays each of the other teams three times. How many games are played?

svetlana [45]

12 each that is the answer

8 0

3 years ago

Read 2 more answers

At a local University, it is reported that 81% of students own a wireless device. If 5 students are selected at random, what is

Sphinxa [80]

Answer:

34.87% probability that all 5 have a wireless device

Step-by-step explanation:

For each student, there are only two possible outcomes. Either they own a wireless device, or they do not. The probability of a student owning a wireless device is independent from other students. So we use the binomial probability distribution to solve this question.

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.

81% of students own a wireless device.

This means that $p = 0.81$

If 5 students are selected at random, what is the probability that all 5 have a wireless device?

This is P(X = 5) when n = 5. So

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

$P(X = 5) = C_{5,5}.(0.81)^{5}.(0.19)^{0} = 0.3487$

34.87% probability that all 5 have a wireless device

5 0

3 years ago

suppose that you plan on taking a summer job selling magazines subscriptions . the magazine company will help you pay $0.75 for

alina1380 [7]

Answer:

Money earned by selling 175 magazine subscriptions will be 3176.25

Solution:

Given that you are planning to take a summer job selling magazine subscription.

For first subscription, magazine company will help you to pay $0.75

For each additional subscription sold, magazine company will pay you $0.20 more than what was paid for previous subscription.

So for second subscription, payments will be = 0.75 + 0.20 = 0.75 + 0.20 x 1

And for third subscription, payments will be = 0.75 + 0.20 = 0.75 + 0.20 x 2

Generalizing for nth subscription we get

Payments for nth subscription = 0.75 + 0.20(n-1)

so here we can see that arithmetic sequence is formed, having first term

$a_1 = 0.75$ and common difference = d = 0.20

We need to determine sum of above arithmetic sequence for n = 175

Formula for sum of arithmetic sequence is as follows 

$\mathrm{S}_{\mathrm{n}}=\frac{n}{2}[2 a+(n-1) d]$

In our case n = 175, a = 0.75, d = 0.20

$\begin{array}{l}{=>\mathrm{S}_{175}=\frac{175}{2}[(2 \times 0.75)+(175-1) 0.20]} \\\\ {=>\mathrm{S}_{175}=\frac{175}{2}[1.5+(174 \times 0.20)]} \\\\ {\Rightarrow \mathrm{S}_{175}=\frac{175}{2} \times 36.3=3176.25}\end{array}$