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2 years ago

If a = 12 and 120% of a is equal to 80\% of bthen what is a + b ?

Mathematics

1 answer:

Novosadov [1.4K]2 years ago

4 0

Answer:

The answer is 30

Step-by-step explanation:

First you have to find 120% of a (12).

$\frac{12}{1} \times \frac{120}{100} = 14.4$

Therefore; 14.4 is 80% of b, and we are trying to find 100% of b

$14.4 = 80\% \\ x = 100\%$

we do not know what is 100% therefore we call it *x*. In order to find this unknown value *x* we cross multiply.

$14.4 \times 100\% = 80\% \times x$

This is the same as saying;

$14.4 \times 1 = x \times \frac{4}{5}$

100% percent would be 1 because it is the whole number we are trying to find. The 80% would be 4/5. To get 4/5 you can simply break down 80/100 ( this is 80% as a fraction).

so the new equation is: 14.4= 4/5x

We divide both sides by 4/5. Then we will get x tobe equal to 18. Therefore b is 18. We were asked to find (a + b) so. 18+12 = 30

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$P(x \ge 5) = 1.000$ ---- At least 5 from marketing departments are extroverts

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Step-by-step explanation:

See comment for complete question

The question is an illustration of binomial probability where

$P(x) = ^nC_x * p^x * (1 - p)^{n-x}$

$(a):\ P(x \ge 5)$

$n = 15$ --- marketing personnel

$p = 75\%$ --- proportion that are extroverts

Using the complement rule, we have:

$P(x \ge 5) = 1 - P(x < 5)$

So, we have:

$P(x < 5) =P(x = 0) + P(x = 1) + P(x = 2) + P(x = 3) + P(x = 4)$

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$P(x \ge 5) = 1 - P(x < 5)$

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$P(x = 0) = 1 * 1 * (0.30)^5$

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<h3>Combination formula: </h3>

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by:

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To learn more about the combination formula, you can take a look at brainly.com/question/25821700

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