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BaLLatris [955]
3 years ago
15

The sum of 3 and 7 times a number is 45

Mathematics
1 answer:
san4es73 [151]3 years ago
6 0

Answer:

4.5

Step-by-step explanation:

The sum of 3 and 7 is 10

then what number to you multiply 10 by to get 45

45 ÷ 10 = 4.5

so the answer is 4.5

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A snack bar weighs 61g, and 10% of the weight is apple. How many
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Answer:

61×10/100

=610/100

=6.1 g

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16. A telemarketer makes six phone calls per hour and is able to make a sale on 30% of these contacts. During the next two hours
Reika [66]

Answer:

a) 23.11% probability of making exactly four sales.

b) 1.38% probability of making no sales.

c) 16.78% probability of making exactly two sales.

d) The mean number of sales in the two-hour period is 3.6.

Step-by-step explanation:

For each phone call, there are only two possible outcomes. Either a sale is made, or it is not. The probability of a sale being made in a call is independent from other calls. 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.

A telemarketer makes six phone calls per hour and is able to make a sale on 30% of these contacts. During the next two hours, find:

Six calls per hour, 2 hours. So

n = 2*6 = 12

Sale on 30% of these calls, so p = 0.3

a. The probability of making exactly four sales.

This is P(X = 4).

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

P(X = 4) = C_{12,4}.(0.3)^{4}.(0.7)^{8} = 0.2311

23.11% probability of making exactly four sales.

b. The probability of making no sales.

This is P(X = 0).

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

P(X = 0) = C_{12,0}.(0.3)^{0}.(0.7)^{12} = 0.0138

1.38% probability of making no sales.

c. The probability of making exactly two sales.

This is P(X = 2).

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

P(X = 2) = C_{12,2}.(0.3)^{2}.(0.7)^{10} = 0.1678

16.78% probability of making exactly two sales.

d. The mean number of sales in the two-hour period.

The mean of the binomia distribution is

E(X) = np

So

E(X) = 12*0.3 = 3.6

The mean number of sales in the two-hour period is 3.6.

4 0
3 years ago
Last year, 400 signed up to take a virtual kickboxing class. This year, there was a 5% increase in registrations. How many peopl
ale4655 [162]

Answer:

420 people

Step-by-step explanation:

400*1.05=420

3 0
3 years ago
I need help fast please and no fies
givi [52]

Answer:

x=-16

Step-by-step explanation:

from x=-3 to get to y=12 u need to multiply x=-3 by -4 to get to 12 so for y=64 u need to divide by -4 which equals x=-16

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Which group of number are all perfect squares
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C: 9 ( = 3^2), 49 ( = 7^2), 81 ( = 9^2) 

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