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3 years ago

Jill can answer 50 math questions every 20 minutes.

Mathematics

2 answers:

antoniya [11.8K]3 years ago

6 0

12 - 30
36- 90
hope that helps!

Artemon [7]3 years ago

3 0

Answer:

12- 30

36- 90

Step-by-step explanation:

if she can answer 50 in 20 mins then that means she is answering 2.5 questions in 1 min and then you must multiply 2.5 by the number of mins she has making it

12 x 2.5= 30

36 x 2.5= 90

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Describe what your first step would be to solve the equation below : <br> 2 (x+7) = -4x + 14

Andrej [43]

Answer:

The first step to solve the equation below is to first distribute the 2 to (x+7)

Step-by-step explanation:

2 (x+7) = -4x + 14

2x + 14 = -4x + 14

3 0

3 years ago

Read 2 more answers

The feet of the average adult woman are 24.6 cm long, and foot lengths are normally distributed. If 16% of adult women have feet

nevsk [136]

Answer:

Approximately 16% of adult women have feet longer than 27.2 cm.

Step-by-step explanation:

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

The feet of the average adult woman are 24.6 cm long

This means that $\mu = 24.6$

16% of adult women have feet that are shorter than 22 cm

This means that when $X = 22$ , Z has a p-value of 0.16, so when $X = 22, Z = -1$ . We use this to find $\sigma$

$Z = \frac{X - \mu}{\sigma}$

$-1 = \frac{22 - 24.6}{\sigma}$

$-\sigma = -2.6$

$\sigma = 2.6$

Approximately what percent of adult women have feet longer than 27.2 cm?

The proportion is 1 subtracted by the p-value of Z when X = 27.2. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{27.2 - 24.6}{2.6}$

$Z = 1$

$Z = 1$ has a p-value of 0.84.

1 - 0.84 = 0.16

0.16*100% = 16%.

Approximately 16% of adult women have feet longer than 27.2 cm.

3 0

3 years ago

Factorize: x²+2+1/x²

andrew-mc [135]

$x^{2}+\frac{1}{x^{2}}+2=\boxed{\left(x+\frac{1}{x} \right)^{2}}$

8 0

2 years ago

What is the value of y if 13/9 = y/18

Maslowich

Answer:

$y=26$

Step-by-step explanation:

1. Swap sides

$\frac{13}{9}=\frac{y}{18}$

Swap sides:

$\frac{y}{18}=\frac{13}{9}$

2. Isolate the y

$\frac{y}{18}=\frac{13}{9}$

Multiply to both sides by 18:

$\frac{y}{18}\cdot 18=\frac{13}{9}\cdot 18$

Group like terms:

$\frac{1}{18}\cdot 18y=\frac{13}{9}\cdot 18$

Simplify the fraction:

$y=\frac{13}{9}\cdot 18$

Multiply the fractions:

$y=\frac{13\cdot 18}{9}$

Simplify the arithmetic:

$y=26$

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Why learn this:

Linear equations cannot tell you the future, but they can give you a good idea of what to expect so you can plan ahead. How long will it take you to fill your swimming pool? How much money will you earn during summer break? What are the quantities you need for your favorite recipe to make enough for all your friends?
Linear equations explain some of the relationships between what we know and what we want to know and can help us solve a wide range of problems we might encounter in our everyday lives.

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Terms and topics

Linear equations with one unknown

The main application of linear equations is solving problems in which an unknown variable, usually (but not always) x, is dependent on a known constant.

We solve linear equations by isolating the unknown variable on one side of the equation and simplifying the rest of the equation. When simplifying, anything that is done to one side of the equation must also be done to the other.

An equation of:

$ax+b=0$

in which $a$ and $b$ are the constants and $x$ is the unknown variable, is a typical linear equation with one unknown. To solve for $x$ in this example, we would first isolate it by subtracting $b$ from both sides of the equation. We would then divide both sides of the equation by $a$ resulting in an answer of: