Simplify: (a) -2 + 3 8 + ( −1 5 )

If two sides of a rectangle are 5 units and 9 units, what is the perimeter?

Mariana [72]

The perimeter is 28 bc 5+5 is 10 and 9+9 is 18 so if you add 10 and 18 you get 28. Hope it helps:)
(please mark brainliest )

3 0

3 years ago

A girl starts to walk to her school, which is 20 miles away, at 6:50 and at a rate of 3 miles per hour. After a while, her dad p

Alexeev081 [22]

The girl walked a distance of $\boxed{{\mathbf{5 miles}}}$ in her way.

Further explanation:

The time can be calculated as,

${\text{ time}}=\frac{{{\text{distance}}}}{{{\text{speed}}}}$

Given:

It is given that a girl stands 20 miles away from the school at $6:50{\text{ am}}$ and she started walking at the rate of $3{\text{ mi/hr}}$ and then after some time her dad pick up and he drives at the rate of $30{\text{ mi/hr}}$ . They reach the school at $9:00{\text{ am}}$ .

Step by step explanation:

Step 1:

Consider $x$ as the distance she walked in her way.

The speed of the girl when she walked is $3{\text{ mi/hr}}$ .

Now use the formula of time to obtain the walk time.

$\begin{gathered}{\text{ walktime}}=\frac{{{\text{distance walked}}}}{{{\text{walking speed}}}}\hfill\\{\text{ walktime}}=\frac{x}{3}\hfill\\\end{gathered}$

Since the total distance is $20{\text{ miles}}$ .

Then consider $20-x$ as the distance driven by the car.

The driving speed is $30{\text{ mi/hr}}$ .

Now use the formula of time to obtain the drive time.

$\begin{gathered}{\text{drive time}}=\frac{{{\text{distance travelled by car }}}}{{{\text{ speed of car}}}}\hfill\\{\text{drive time}}=\frac{{20-x}}{{30}} \hfill\\\end{gathered}$

Step 2:

Now we calculate the total time took by girl to reach the school.

$9:00-6:50={\text{2 hrs 10 min}}$

Now convert the timing into hours as,

$\begin{aligned}2{\text{ hours 10 minutes}}&=2+\frac{{10}}{{60}}\\&=2\frac{1}{6}\\&=\frac{{13}}{6}{\text{ hrs}}\\\end{aligned}$

Step 3:

Total time is the sum of drive time and walk time.

The total time can be expressed as,

$\frac{x}{3}+\frac{{20-x}}{{30}}=\frac{{13}}{6}$

Now solve the above equation by cross multiply method.

$\begin{aligned}\frac{x}{3}+\frac{{20-x}}{{30}}&=\frac{{13}}{6}\hfill\\\frac{{10x+20-x}}{{30}}&=\frac{{13}}{6}\hfill\\\frac{{9x+20}}{{30}}&=\frac{{13}}{6}\hfill\\6\left({9x+20}\right)&=13\left({30}\right)\hfill\\\end{aligned}$

Now simplify the further equation.

$\begin{aligned}6\left({9x+20}\right)&=13\left({30}\right)\hfill\\54x+120&=390\hfill\\54x&=390-120\hfill\\54x&=270\hfill\\\end{aligned}$

Simplify the further equation.

$\begin{aligned}54x&=270\hfill\\x&=\frac{{270}}{{54}}\hfill\\x&=\frac{{45}}{9}\hfill\\x&=5\hfill\\\end{gathered}$

Therefore, the girl walked 5 miles.

Learn more:

Learn more about the distance between the points brainly.com/question/6278187

Learn more about the equivalent fraction brainly.com/question/952259

Learn more about midpoint of the segment brainly.com/question/3269852

Answer details:

Grade: High school

Subject: Mathematics

Chapter: Speed, distance and time

Keywords: girl, distance, drive, walk, drive time, dad, speed, travelled, formula, cross multiply, fraction, number, multiply, addition, subtraction, equation, school

8 0

4 years ago

Read 2 more answers

To go on the class trip, chang needs at least $125. he has saved $45, and he makes $7 an hour at his job. what is the minimum nu

Murljashka [212]

The total amount that Chang will received from his wages is the product of his hourly wage times the number of hours he has worked (n). His total savings should not be less than $125. The equation that best describes the situation is,
45 + 7n ≥ 125
Solving for n in the inequality gives an answer of n≥11.42 hours. Thus, he needs to work for at least 12 hours.

6 0

3 years ago

Read 2 more answers

Pleeeeeese Solve 2x +7-3

Alex

Hey there! :D

2x+7-3

The only thing you can simplify is 7 and 3.

7-3= 4

2x+4 <=== simplified expression

I hope this helps!
~kaikers

3 0

4 years ago

A jar contains four red marbles and six green marbles. You randomly select a marble from the jar, with replacement. The random v

ioda

Answer:

The probability of getting exactly two read marbles is P = 0,003456%

Step-by-step explanation:

So, each of the following sequences are the desired results(I will use R for a red marble and G for a green marble).

S(1) = R-R-G-G

S(2) = R-G-R-G

S(3) = R-G-G-R

S(4) = G-R-R-G

S(5) = G-R-G-R

S(6) = G-G-R-R

In all, considering there are replacement, there can be 10*10*10*10 = 10000 total sequences, so the probability of getting exactly two read marbles is

P = \frac{P(S(1)) + P(S(2)) + P(S(3)) + P(S(4)) + P(S(5)) + P(S(6))}{10000}

where

P(S(1)) = P(S(2)) = P(S(3)) = P(S(4)) = P(S(5)) = P(S(6)) = (0.4)^{2}*(0.6)^{2} = 0.16*0.36 = 0.0576.

The probability of getting exactly two read marbles is

P = \frac{6*0.0576}{10000} = 0,003456%

3 0

4 years ago