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2 years ago

Write the equivalent expression to the sum of the expressions 3a2 + 3a and -3a - 3a2

Mathematics

1 answer:

ASHA 777 [7]2 years ago

7 0

Answer:

$3 {a}^{2} + 3a + (- 3 {a}^{2} - 3a) \\ = 3 {a}^{2} - 3 {a}^{2} + 3a - 3a \\ = 0 \\ thank \: you$

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Assume that there are an equal number of births in each month so that the probability is that a person chosen at random was born

NikAS [45]

Answer:

0.2773 = 27.73% probability that at the May celebration, exactly two members of the group have May birthdays

Step-by-step explanation:

For each person, there are only two possible outcomes. Either they have a birthday in May, or they do not. The probability of a person having a birthday in May is independent of any other person. This means that the binomial probability distribution is used 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.

Probability of a person being in May:

May has 31 days in a year of 365. So

$p = \frac{31}{365} = 0.0849$

Group of 20 friends:

This means that $n = 20$

What is the probability that at the May celebration, exactly two members of the group have May birthdays?

This is P(X = 2).

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

$P(X = 2) = C_{20,2}.(0.0849)^{2}.(0.9151)^{18} = 0.2773$

0.2773 = 27.73% probability that at the May celebration, exactly two members of the group have May birthdays

3 0

2 years ago

the scale of a model railroad set is 3.5 millimeters to one foot if the length of a model car in the set is 150 millimeters what

Montano1993 [528]

$\bf \begin{array}{ccll} \stackrel{mm}{model}&\stackrel{ft}{actual}\\ \cline{1-2} 3.5&1\\ 150&x \end{array}\implies \cfrac{3.5}{150}=\cfrac{1}{x}\implies x=\cfrac{150\cdot 1}{3.5}\implies x\approx 42.86$

6 0

3 years ago

Read 2 more answers

The sides of a quadrilateral whose sides are 85cm 143cm 165cm and 85cm and one of the diagonals is 154cm

yaroslaw [1]

Answer:85cm is kept comstant for a while

Step-by-step explanation:

For 2nd part

1m 80 cm

=1×100cm+ 80 cm

=100cm+ 80 cm

=180cm

#According to question,

If both are added then,

=85cm+180 cm

=265cm

please brainlest

Step-by-step explanation:

7 0

3 years ago

Pedro bought lb of red sand and lb of brown sand to refill his sand box. Both types of sand cost $4.60 a pound. How much did Ped

Doss [256]

If we know that Pedro bought 1 $\frac{1}{4}$ pounds of red sand, and 5 $\frac{1}{2}$ pounds of brown sand, and they both cost $4.60, then we just have to add the individual amounts of sand, since they cost the same.

$1 \frac{1}{4} + 5 \frac{1}{2} = 6 \frac{3}{4}$

So Pedro bought $6 \frac{3}{4}$ lbs of sand overall. Now, we just need to multiply the cost per pound by the total amount of sand he bought.

$6 \frac{3}{4} * 4.6 = 31.05$

Pedro spent $31.05 on sand, which is answer choice B.
Hope that helped =)

4 0

3 years ago

Read 2 more answers

I will pick brainliest first come, first serve! I need help! Give me an answer that makes sense!

nordsb [41]

Step-by-step explanation:

Total amount of apples in one bag:

$x + y + z$

Hence, total amount of apples in two bags:

$2(x + y + z)$

$2x + 2y + 2z$

$x + x + y + y + z + z$

Hence, B, D and E are correct.

A is incorrect because you are adding 2 more apples on top of the total amount of apples in one bag, and you cannot assume that there are 2 apples in each bag.

C is incorrect because you are multiplying the apples together, but you are supposed to add them up to find the total.

F is incorrect because you are finding 1/2 a bag.

3 0

3 years ago