All Answers

+118725

CynthiaElston:
what is the fraction 100/3 times 2

MelodyFeb 27, 2014

+33666

COxford:
Water collected in a rain barrel can be used to water plants and reduce city water use. Water flowing from an open rain barrel has a velocity v=8h1/2, where v is in feet per second and h is the height of the water in feet. Find the height of the water if it is flowing at 16 feet per second.

Square both sides of the equation; rearrange to get h on its own; plug in the given value of v and calculate h, (I'm assuming that the units of the 'number' 8 are such that the result will be so many feet!).

AlanFeb 27, 2014

+33666

If N is the number of enrolled students then the question says 90% of N equals 4,248.

90% as a fraction is 90/100 or 9/10, so (9/10)xN = 4248

Divide both sides by 9 and multiply both sides by 10 to find N

AlanFeb 27, 2014

+118725

iLikeFriedChicken:
The boat could sail at 6 times the speed of the current in the river. Thus, the boat could go 100 miles upstream in 3 hours more than it took to go 14 miles downstream. What was the speed of the boat in still water?

What a great question.

Let the speed of the boat in still water be x miles/hour
then
the speed of the current must be x/6 miles/hour

When travelling against the current the speed will be (x-x/6) = 5x/6 miles/hour OR you can say 6/(5x) hours/mile
When travelling with the current the speed will be (x+x/6) = 7x/6 miles/hour OR you can say 6/(7x) hours/mile

The boat travels upstream 100miles
6/(5x) hours/mile * 100miles = 600/(5x) hours = 120/x hours. (The miles cancel out - and yes you can cancel the units like that)

The boat travels downstream 14 miles
6/(7x) hours/mile * 14 miles = 12/x hours

The boat travels 3 hours longer for the upstream journey so
12/x + 3 = 120/x
3 = 108/x
1/3 = x/108
108/3 = x
x = 36
So in still water the boat will travel at 36 miles/hour

MelodyFeb 27, 2014

+118725

jayant:
what is tan inverse of 0.74

It is
inverse tan 0.74
or
arctan 0.74

atan(0.74)

MelodyFeb 27, 2014

+118725

redsaxdude:
in right triangle abc sin a = 1/2. what is cos a

Draw the triangle
use pythagoras to work out the other side
read cos a of the triangle.

MelodyFeb 27, 2014

+118725

toni:
6.767x10^23*12.0/6.022x10^23

I don't know if this is the question that you intended but it is certainly the question that you wrote.
If you meant something different then you needed to use brackets.

[ 6.767x10^23*12.0/6.022 ] x10^23

[ (6.767*12/6.022) * 10 ²³ * 10 ²³

13.48455663 * 10 ²⁶

1.348 * 10 ²⁷ (to 4 significant figures)

MelodyFeb 27, 2014

+118725

Johyi:
Would like to ask your help on how to solve for k and t
(y-5.74)=(ke-(x-99294)t) (1)
(y-5.64)=(ke-(x-265792)t) (2)
(y-5.05)=(ke-(x-500000)t) (3)

Are all of these equations supposed to be solved simultaneously?

I think I will just look at the first 2
(1)-(2)
-5.74- - 5.64 = (-99294 - - 265792)t

-0.1 = 166498 t
t = - 6.006 * 10 ^-7 (Correct to 4 significant figures)
Now it gets horrible and I don't want to think about it at the moment.
You muck around with it and see how you go.
I am still not sure what I am being asked to do.
I am just assuming that t and k must be the same for all three equations and that they are constants.

MelodyFeb 27, 2014

+118725

AvaMaria1234:
What is the domain?

Domain is all the possible x values for a given function.

MelodyFeb 27, 2014

+118725

kitty<3:
2(4x-3)-8=4+2x

First, distribute the 2 into (4x-3), so:
8x-6 -8 = 4 +2x

Simplify the left side.
8x-14 = 4 + 2x
Add 14 to both sides (to move it from the left to the right side.)
8x = 16 + 2x
Now subtract 2x from both sides.
4x = 16
Divide by 4.

x = 4

--------------------------------------------

Sorry Kitty but 4+14 is not 16.

MelodyFeb 27, 2014

+118725

sUsHiBoY:
How many different 2-player bridge teams could be formed from 5 players?

5C2 = 10

MelodyFeb 27, 2014

6.767x10^23*12.0/6.022x10^23

GuestFeb 27, 2014

+5478

2(4x-3)-8=4+2x

First, distribute the 2 into (4x-3), so:
8x-6 -8 = 4 +2x

Simplify the left side.
8x-14 = 4 + 2x
Add 14 to both sides (to move it from the left to the right side.)
8x = 16 + 2x
Now subtract 2x from both sides.
4x = 16
Divide by 4.

x = 4

kitty<3Feb 27, 2014

+5478

Hi Ana,

I2z – 1 = 32

add 1 to both sides.
12z = 33
then divide both sides by 12 to get z.
z = 33/12

z = 2.75

kitty<3Feb 27, 2014

+118725

JEnna:
80 girls and boys are planed for a movie, there are in a ratio of 6 girls to 2 boy how many girls are there

6 out of every 8 chldren are girls

6/8 * 80 = 60 girls

MelodyFeb 27, 2014

+118725

poekakitie:
:D how can i draw a graph?

with a pencil and a ruler

MelodyFeb 27, 2014

+135

Anna Sun:
A 25 foot ladder leans against a building. The ladder's base is 13.5 feet from the building. Find the angle which the makes with the ground.

This question is k*****g me!

Hey Anna Sun!

The cosine of the angle is the base divided by the length.
Take the inverse cosine to find the angle...

I like SerenaFeb 27, 2014

Oh, okay. That makes a lot more sense now. Thanks for the help!

GuestFeb 27, 2014

+118725

Guest:
what is the Pythagorean theorem

look here
http://www.mathsisfun.com/pythagoras.html

MelodyFeb 27, 2014

+118725

If you want 3 and a half - 2 and a 1/4 + 1/5

(3+1/2)-(2+1/4)+1/5

MelodyFeb 27, 2014

+118725

Guest:
Would it not be:

tan 3 = 17.5/x (opposite leg / adjacent leg)
17.5 x tan 3 = x
0.9171361374525 = x

I tried that, but the answer seems too small to be correct, unless I am doing something wrong or missing a step.

First, we have interpreted the question differently. I think the base of the ramp means the ramp itself. You think it means the horizontal distance. Either of us could be correct. the question is unclear.
Let us assume that your interpretation is correct.
On the computer we use * instead of x when we mean multiply. So we have

tan3 = 17.5/x
Now the 17.5 is on the TOP. If you chose to get rid of it you would have to divide. I am going to do either.

I am going to turn both sides upside down. (Because I want x on the top)
1/(tan3) = x/17.5
no multiply both sides by 17.5
1/(tan3) * 17.5 = x/17.5 * 17.5
17.5 / tan3 = x

17.5/tan(3)

MelodyFeb 27, 2014

+118725

Guest:
what is the distance formula

140227 distance formula.JPG

MelodyFeb 27, 2014

+118725

needhelp:
what is sqrt3(16)

16root3

unless you mean

sqrt(3*16) = 4root3

MelodyFeb 27, 2014

+118725

vernecia21:
you invest in $7,000 in some stock that will earn 14% annual interest compounded quarterly. how long will it take for the value of the stock to quadruple?

S = P(1+i) ⁿ

P is present value
S is future value = 4P
i = 0.14/4 = 0.035
n= unknown

4P = P*(1+0.035) ⁿ
4 = 1.035 ⁿ

log4 = log1.035 ⁿ

log4 = n log1.035

log4 / log1.035 = n (quarters)

years = (log4 / log1.035) / 4

(log(4)/log(1.035))/4=

MelodyFeb 27, 2014

Feb 26, 2014

+118725

chulsey:
joyce has a piece of property with an area that is 9/10 acres. she wishes to divide into 2 equal parcels. how many acres is each parcel?

9/10 divided by 2 =

MelodyFeb 26, 2014

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