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4 years ago

Friendly numbers and mental math

Mathematics

2 answers:

Mars2501 [29]4 years ago

6 0

what about friendly numbers and mental math?

ElenaW [278]4 years ago

6 0

Numbers are your friends

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For a recipe, Henry uses 3 cups of white sugar for each cup of brown sugar. How many cups of brown sugar does Henry use when he

Andrej [43]

Answer:

1/3

Step-by-step explanation:

8 0

3 years ago

What is the area of the following circle? the radius is 1 unit

Brilliant_brown [7]

Answer:

The area is π= 3.14 approx

Hope it helps!

Step-by-step explanation:

Area of circle = πr^2

Radius= r = 1 unit

So area,

= 3.14*(r)^2

= 3.14*(1)^2

= 3.14*1

= 3.14 or π if you want the specific answer

6 0

3 years ago

Read 2 more answers

A student takes a multiple-choice test that has 11 questions. Each question has five choices. The student guesses randomly at ea

marissa [1.9K]

Answer:

a) P(6) = 0.0097

b) P(More than 3) = 0.1611

Step-by-step explanation:

For each question, there are only two possible outcomes. Either it is guessed correctly, or it is not. Questions are independent of each other. 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 student takes a multiple-choice test that has 11 questions.

This means that $n = 11$

Each question has five choices.

This means that $p = \frac{1}{5} = 0.2$

(a) Find P (6)

This is P(X = 6).

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

$P(X = 6) = C_{11,6}.(0.2)^{6}.(0.8)^{5} = 0.0097$

P(6) = 0.0097

(b) Find P (More than 3).

Either P is 3 or less, or it is more than three. The sum of the probabilities of these outcomes is 1. So

$P(X \leq 3) + P(X > 3) = 1$

We want P(X > 3). So

$P(X > 3) = 1 - P(X \leq 3)$

In which

$P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)$

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

$P(X = 0) = C_{11,0}.(0.2)^{0}.(0.8)^{11} = 0.0859$

$P(X = 1) = C_{11,1}.(0.2)^{1}.(0.8)^{10} = 0.2362$

$P(X = 2) = C_{11,2}.(0.2)^{2}.(0.8)^{9} = 0.2953$

$P(X = 3) = C_{11,3}.(0.2)^{3}.(0.8)^{8} = 0.2215$

$P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.0859 + 0.2362 + 0.2953 + 0.2215 = 0.8389$

Then

$P(X > 3) = 1 - P(X \leq 3) = 1 - 0.8389 = 0.1611$

P(More than 3) = 0.1611

8 0

4 years ago

(-12)÷6+2 pls help math is hard for me

SVEN [57.7K]

The Answer is -3/2

Below is how I got that answer

(-12) / 6+2

-12/ 8 (Simplify the problem by adding 6 and 2, remove the parenthesis).

-3/2 (Simplify -12/8 by dividing it by 4)

4 0

3 years ago

The current cost of gourmet coffee Is $14 per pound At the corner market the cost has increased 10% Per year over the past few y

KonstantinChe [14]

Answer:

$11.57

Step-by-step explanation:

Let's call the price of the coffee two years ago by X.

The price increased 10% per year (that is, the price is multiplied by 1+0.1=1.1) over two years, so the current price is:

X * 1.10 * 1.10 = X * 1.21

If the current price is $14, we have that:

X * 1.21 = 14

X = 14/1.21 = 11.57

The price of the coffee two years ago was $11.57

5 0

3 years ago