Can someone pls help me find the area of this please

Leno4ka [110]

2.5 X 10^-3 is the scientific notation for 0.0025

7 0

3 years ago

Mrs. Clark is Zooming with a certain number of students and 12 students are in the waiting room, she Zoomed with a total of 37 s

kobusy [5.1K]

Answer:

25

Step-by-step explanation:

The students on the screen is the difference between the total number of students she zoomed and the students in the waiting area

37 - 12 = 25

6 0

3 years ago

Need pre-cal help. Will mark best answer brainliest

OlgaM077 [116]

so, let's keep in mind that

$\bf \begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}$

so let's make a quick table of those solutions, say A, B, C solutions with x,y,z liters of acid, with an acidity of 0.25, 0.40 and 0.60 respectively.

$\bf \begin{array}{lcccl} &\stackrel{solution}{quantity}&\stackrel{\textit{\% of }}{amount}&\stackrel{\textit{liters of }}{amount}\\ \cline{2-4}&\\ A&x&0.25&0.25x\\ B&y&0.40&0.4y\\ C&z&0.60&0.6z\\ \cline{2-4}&\\ mixture&78&0.45&35.1 \end{array} \\\\\\ \begin{cases} x+y+z=78\\ 0.25x+0.4y+0.6z=35.1 \end{cases}$

we know she's using "z" liters and those are 3 times as much as "y" liters, so z = 3y.

$\bf \begin{cases} x+y+3y=78\\ x+4y=78\\[-0.5em] \hrulefill\\ 0.25x+0.4y+0.6(3y)=35.1\\ 0.25x+0.4y=1.8y=35.1\\ 0.25x+2.2y=35.1 \end{cases}\implies \begin{cases} x+4y=78\\\\ 0.25x+2.2y=35.1 \end{cases} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ x+4y=78\implies \boxed{x}=78-4y \\\\\\ \stackrel{\textit{using substitution on the 2nd equation}}{0.25\left( \boxed{78-4y} \right)+2.2y=35.1}\implies 19.5-y+2.2y=35.1$

$\bf 1.2y=15.6\implies y=\cfrac{15.6}{1.2}\implies \blacktriangleright y=13 \blacktriangleleft \\\\\\ x=78-4y\implies x=78-4(13)\implies \blacktriangleright x=26 \blacktriangleleft \\\\\\ z=3y\implies z=3(13)\implies \blacktriangleright z=39 \blacktriangleleft \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{25\%}{26}\qquad \stackrel{40\%}{13}\qquad \stackrel{60\%}{39}~\hfill$

5 0

3 years ago

Brooke plays on her schools softball team. Last season she was at bat 500 times and made a safe hit 28% of the time. How is 28%

Gre4nikov [31]

Answer:

28/100

Step-by-step explanation:

5 0

3 years ago

leo knows that each time a digit moves one place to the left in a whole number the value of the digit is 10 times as much. descr

Serga [27]

Answer:

Leo is true for any numbers (including decimal numbers)

Step-by-step explanation:

* Lets explain how to solve the problem

- In number 256

# 6 is the unit digit (one digit)

# 5 is the ten digit (10 digit)

# 2 is the hundred digit (100 digit)

- If we change the number to 2563

# 6 digit is moved 1 place to the left now its place changed from unit

digit to ten digit (from 1 to 10) that means 6 in the second number

is 10 times the 6 in the first number

# 5 digit is moved 1 place to the left now its place changed from ten

digit to hundred digit (from 10 to 100) that means 5 in the second

number is 10 times the 5 in the first number

# 2 digit is moved 1 place to the left now its place changed from

hundred digit to thousand digit (from 100 to 1000) that means 2

in the second number is 10 times the 2 in the first number

- In number 2.345

# 2 is the unit digit (one digit)

# 3 is the tenth digit (1/10 digit)

# 4 is the hundredth digit (1/100 digit)

# 5 is the thousandth digit (1/1000 digit)

- If we change the number to 23.45

# 3 digit is moved 1 place to the left now its place changed from tenth

digit to unit digit (from 1/10 to 1) that means 3 in the second number

is 10 times the 3 in the first number

# 4 digit is moved 1 place to the left now its place changed from

hundredth digit to tenth digit (from 1/100 to 1/10) that means 4 in the

second number is 10 times the 5 in the first number

# 5 digit is moved 1 place to the left now its place changed from

thousandth digit to hundredth digit (from 1/1000 to 1/100) that means

5 in the second number is 10 times the 5 in the first number

∴ Leo is true for any numbers (including decimal numbers)

3 0

3 years ago