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Anyone Wanna Help Me Out with some Math?

06-28-2010, 05:41 PM
#11
Joined: Aug 2009
Location: Next to the Maiden
Posts: 1,990
And after looking at the first one, I made a rookie mistake there.
It takes pipe A, running alone, 18 hours to fill the tank. It takes both pipes, running together, 9.9 hours to fill the tank. How long does it take pipe B, running alone, to fill the tank?
-----
A DATA:
time = 18 hrs/job ; rate = 1/18 jobs/hr
--------------------------------------------
A/B DATA:
time = 9.9 hrs/job ; rate = 1/9.9 job/hr
--------------------------------------------
B DATA:
time = x hrs/job ; rate = 1/x job/hr
----------------------------------------
Equation:
rate + rate = together rate
1/18 + 1/x = 1/9.9
---
9.9x + 9.9*18 = 18x
8.1x = 9.9*18
x = 22 hrs (time required by the B pipe to fill the tank)

Give me some slack, schools out. xD
06-28-2010, 05:44 PM
#12
Joined: Apr 2009
Location: Australia, mate!
Posts: 8,453
I'm too good-looking to know these stuff.

hi

06-28-2010, 07:04 PM
#13
Joined: Dec 2008
Posts: 6,522
Quote:
Originally Posted by DGH94 View Post
And after looking at the first one, I made a rookie mistake there.
It takes pipe A, running alone, 18 hours to fill the tank. It takes both pipes, running together, 9.9 hours to fill the tank. How long does it take pipe B, running alone, to fill the tank?
-----
A DATA:
time = 18 hrs/job ; rate = 1/18 jobs/hr
--------------------------------------------
A/B DATA:
time = 9.9 hrs/job ; rate = 1/9.9 job/hr
--------------------------------------------
B DATA:
time = x hrs/job ; rate = 1/x job/hr
----------------------------------------
Equation:
rate + rate = together rate
1/18 + 1/x = 1/9.9
---
9.9x + 9.9*18 = 18x
8.1x = 9.9*18
x = 22 hrs (time required by the B pipe to fill the tank)

Give me some slack, schools out. xD
Thanks, DGH. This clears it up. I eventually found the first one out on my own. Simple proportion
06-28-2010, 07:42 PM
#14
Joined: Mar 2009
Location: Washington
Posts: 9,132
So thaaaat's why I failed math.

back
06-28-2010, 08:09 PM
#15
Joined: Aug 2009
Location: Next to the Maiden
Posts: 1,990
Quote:
Originally Posted by Kamazar View Post
Thanks, DGH. This clears it up. I eventually found the first one out on my own. Simple proportion
Np. I took Alg2AP this year and got an A, so I SHOULD know this. xD
06-29-2010, 07:53 PM
#16
Joined: Apr 2009
Location: Australia, mate!
Posts: 8,453
How do I find the acute angle between y=2x and y=-2x?

hi
06-29-2010, 08:29 PM
#17
Quote:
Originally Posted by Random_Guy View Post
How do I find the acute angle between y=2x and y=-2x?
Well you'd have to look for it I guess. When was the last time you saw it? And you've checked it's not in any of your pockets right?

In-game name:winegum
XBL GT:winegum21
06-29-2010, 08:46 PM
#18
Joined: Aug 2009
Location: Next to the Maiden
Posts: 1,990
Quote:
Originally Posted by Random_Guy View Post
How do I find the acute angle between y=2x and y=-2x?
If you're serious, what you want to do is draw a third line to make a right triangle. It should be the reciprocal of one of the lines if I remember correctly. Then find the distance of two of the sides of the triangle, and then use trig to find the angle needed.
BUT, the two equations you gave me don't form an acute angle, they form an angle of 120 degrees, an obtuse angle. So technically you're question is obsolete or I'm a complete retard.
06-29-2010, 08:50 PM
#19
Joined: Feb 2009
Location: the next whiskey bar
Posts: 5,557
Quote:
Originally Posted by DGH94 View Post
If you're serious, what you want to do is draw a third line to make a right triangle. It should be the reciprocal of one of the lines if I remember correctly. Then find the distance of two of the sides of the triangle, and then use trig to find the angle needed.
BUT, the two equations you gave me don't form an acute angle, they form an angle of 120 degrees, an obtuse angle. So technically you're question is obsolete or I'm a complete retard.
then there's also an angle of 60deg
06-30-2010, 05:35 PM
#20
Joined: Apr 2009
Location: Australia, mate!
Posts: 8,453
Nvm.

hi