All categories

3 years ago

Pleaseee help me I don’t understand. With explanation pleasee thank you

Mathematics

2 answers:

enot [183]3 years ago

3 0

Answer:

20 girls

Step-by-step explanation:

3:5; this means that if there were 8 students, 3 would be girls and 5would be girls. Using this info we can multiply the ratio by a umber that will turn the total amount of students to 32.

4(3:5)=12:20

12+20=32

12 boys and 20 girls in a class of 32 students.

andre [41]3 years ago

3 0

answer. the answer your looking for is 20

You might be interested in

Using the digits 0-9 what is the smallest 7 digit number without using consecutive numvers

9966 [12]

1023456. As it is a 7 digit number, 0 cant be put first. Hence the digit 1 goes first. and then come 0. After that, as there is no repetition allowed, we skip the number 1 and place 2. Then, we go chronologically until we have a total of 7 digits <span />

5 0

3 years ago

Volume of a cube<br> 3.8 ft<br> 1.1 ft

balu736 [363]

Where’s the photo? But I need to answer with a photo 3.8 ft and 1.1 ft equals 4.9 ft

7 0

3 years ago

Finding circumference.

Vsevolod [243]

50.24. I used the formula for area of a circle and that’s what I got.

6 0

2 years ago

Read 2 more answers

How do you integrate arctan(x dx? i think that if you simplify the integral you get:?

Temka [501]

Integration by parts will help here. Letting $u=\arctan x$ and $\mathrm dv=\mathrm dx$ , you end up with $\mathrm du=\dfrac{\mathrm dx}{1+x^2}$ and $v=x$ . Now

$\displaystyle\int\arctan x\,\mathrm dx=uv-\int v\,\mathrm du$
$\displaystyle\int\arctan x\,\mathrm dx=x\arctan x-\int\frac x{1+x^2}\,\mathrm dx$

For the remaining integral, setting $y=1+x^2$ gives $\dfrac{\mathrm dy}2=x\,\mathrm dx$ , so

$\displaystyle\int\frac x{1+x^2}\,\mathrm dx=\frac12\int\frac{\mathrm dy}y=\frac12\ln|y|+C=\frac12\ln(1+x^2)+C$

Putting everything together, you end up with

$\displaystyle\int\arctan x\,\mathrm dx=x\arctan x-\frac12\ln(1+x^2)+C$

6 0

3 years ago

I don't know how to do this or what i'm doing plz help

mote1985 [20]

recalling that d = rt, distance = rate * time.

we know Hector is going at 12 mph, and he has already covered 18 miles, how long has he been biking already?

$\bf \begin{array}{ccll} miles&hours\\ \cline{1-2} 12&1\\ 18&x \end{array}\implies \cfrac{12}{18}=\cfrac{1}{x}\implies 12x=18\implies x=\cfrac{18}{12}\implies x=\cfrac{3}{2}$

so Hector has been biking for those 18 miles for 3/2 of an hour, namely and hour and a half already.

then Wanda kicks in, rolling like a lightning at 16mph.

let's say the "meet" at the same distance "d" at "t" hours after Wanda entered, so that means that Wanda has been traveling for "t" hours, but Hector has been traveling for "t + (3/2)" because he had been biking before Wanda.

the distance both have travelled is the same "d" miles, reason why they "meet", same distance.

$\bf \begin{array}{lcccl} &\stackrel{miles}{distance}&\stackrel{mph}{rate}&\stackrel{hours}{time}\\ \cline{2-4}&\\ Hector&d&12&t+\frac{3}{2}\\[1em] Wanda&d&16&t \end{array}\qquad \implies \begin{cases} \boxed{d}=(12)\left( t+\frac{3}{2} \right)\\[1em] d=(16)(t) \end{cases}$

$\bf \stackrel{\textit{substituting \underline{d} in the 2nd equation}}{\boxed{(12)\left( t+\frac{3}{2} \right)}=16t}\implies 12t+18=16t \\\\\\ 18=4t\implies \cfrac{18}{4}=t\implies \cfrac{9}{2}=t\implies \stackrel{\textit{four and a half hours}}{4\frac{1}{2}=t}$

7 0

3 years ago