The product of a number and 3 increased by 9 is less than -42 TRANSLATE

Sketch the parabola y = x2 + 4x – 5.

Daniel [21]

Step-by-step explanation:

y=(x+5)(x-1)

y=-5 x=0

y=0. x=-5

y=0 x=1

now you got the points so graph will be like

5 0

2 years ago

The average heights of x number of girls and 15 boys is 123. if the average heights of boys is 125 and that of girls is 120.find

mamaluj [8]

Answer:

$x = 10$ . In other words, there number of girls is $10$ .

Step-by-step explanation:

The average of a number of measurements is equal to the sum of these measurements over the number of measurements.

$\displaystyle \text{Average} = \frac{\text{Sum of measurements}}{\text{Number of measurements}}$ .

Rewrite to obtain:

$\begin{aligned}& \text{Sum of measurements}= (\text{Number of measurements}) \times (\text{Average}) \end{aligned}$ .

For this question:

$\begin{aligned}& \text{Sum of heights of boys} \\ &= (\text{Number of boys}) \times (\text{Average height of boys}) \\ &= 15 \times 125 = 1875\end{aligned}$ .

$\begin{aligned}& \text{Sum of heights of girls} \\ &= (\text{Number of girls}) \times (\text{Average height of girls}) \\ &= x \times 120 = 120\, x\end{aligned}$ .

Therefore:

$\begin{aligned}& \text{Sum of boys and girls} \\ &= \text{Sum of heights of boys} + \text{Sum of heights of girls}\\ &= 1875 + 120\, x\end{aligned}$ .

On the other hand, there are $(15 + x)$ boys and girls in total. Using the formula for average:

$\begin{aligned}& \text{Average height of boys and girls} \\ &= \frac{\text{Sum of heights of boys and girls}}{\text{Number of boys and girls}} \\ &= \frac{1875 + 120\, x}{15 + x}\end{aligned}$ .

From the question, this average should be equal to $123$ . In other words:

$\displaystyle \frac{1875 + 120\, x}{15 + x} = 123$ .

Solve this equation for $x$ to obtain:

$1875 + 120\, x= 123\, (15 + x)$ .

$(123 - 120)\, x = 1875 - 123 \times 15$ .

$x = 10$ .

In other words, the number of girls here is $10$ .

5 0

3 years ago

A student who is trying to write a paper for a course has a choice of two topics, A and B. If topic A is chosen, the student wil

algol13

Answer:

P(Topic A) = 0.91

P(Topic B) = 0.9163

The student should choose Topic B to maximize the probability of writing a good paper because P(Topic B)>P(Topic A).

Step-by-step explanation:

If Topic A is chosen, 2 books will be ordered (n=2)

If topic B is chosen, 4 books will be ordered (n=4)

Probability that a book arrives in time (p) = 0.7

Probability that a book does not arrive in time (q) = 1 - p = 1 - 0.7 = 0.3

We will use the binomial distribution to find out which topic should the student choose to maximize the probability of writing a good paper. The binomial distribution formula is:

P(X=x) = ⁿCˣ pˣ qⁿ⁻ˣ

where p = probability of success

q = probability of failure

n = total no. of trials

x = no. of successful trials

For Topic A, n = 2, p=0.7 and q=0.3. If topic A is chosen, the student will use at least half the books i.e. he will use either 1 or 2 books. So,

P(Topic A) = P(X=1) + P(X=2)

=²C₁ (0.7)¹(0.3)²⁻¹ + ²C₂ (0.7)²(0.3)²⁻²

= 0.42 + 0.49

P(Topic A) = 0.91

For topic B, n=4, p=0.7 and q=0.3. If topic B is chosen, the student will choose 2 or more books i.e. 2, 3 or 4 books.

P(Topic B) = P(X=2) + P(X=3) + P(X=4)

= ⁴C₂ (0.7)²(0.3)⁴⁻² + ⁴C₃ (0.7)³(0.3)⁴⁻³ + ⁴C₄ (0.7)⁴(0.3)⁴⁻⁴

= 0.2646 + 0.4116 + 0.2401

P(Topic B) = 0.9163

The student should choose Topic B to maximize the probability of writing a good paper because P(Topic B)>P(Topic A) as calculated above.

3 0

3 years ago

An art class is making a mural for the school that has a triangle drawn in the middle. The length of the bottom of the triangle

Arte-miy333 [17]

Answer:

7

Step-by-step explanation:

4 0

2 years ago

subtract the product of 3 and 4 from 36. then divide the quotient of 9 and 3, subtracted from fifteen

Butoxors [25]

The first one is 24, and the second one is 12

4 0

2 years ago

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