Solving Rational Equations

zee-f · 2011-09-20 10:54:11

540 + 24y + -22y = 660 + 22y + -22y
540 + 2y = 660 + 22y + -22y

22y + -22y = 0
540 + 2y = 660 + 0
540 + 2y = 660
540 + -540 + 2y = 660 + -540
540 + -540 = 0
0 + 2y = 660 + -540
2y = 660 + -540
660 + -540 = 120
2y = 120
y = 60

zee-f · 2011-09-20 10:55:37

and if i mix 60 quarts of b with 30 quarts of A ill have a 22% solution of butterfat.

zee-f · 2011-09-20 10:56:47

but i choose (d) for 17 it was incorrect any idea why?

bobbym · 2011-09-20 10:57:47

Hi zee-f;

What problem is that? What were the choices?

I am going to take a little break, see you later.

Bob · 2011-09-20 19:32:09

hi zee-f

In answer D, the second row mixture is incorrect.

The table says .24x, but it should be .24(90-x) ie. quarts multplied by percent.

There is another table that has exactly the same entries except it has the correct entry for mixture type B.

Once you have chosen this table you can solve the problem with an equation just in x (no y needed).

What you wrote in post#56 is correct.

In 20, answer D is correct. I'm still trying to get my head around the wording in 19.

LATER EDIT: Got it. I don't get answer D this time.

What working have you got for this one?

Bob

Last edited by Bob (2011-09-20 19:53:14)

zee-f · 2011-09-20 22:18:22

I think F is correct the second row mixture is correct .24(90-x) for 17

for 20 i got it correct but 19 i choose F and it was incorrect

zee-f · 2011-09-20 22:20:34

bobbym

am talking about 17 these are the choices in the upload

Type A cream is 18% butterfat and type B cream is 24% butterfat. Set up a table to help you determine how many quarts of each type of cream must be used to create a 90 quart mixture that is 22% butterfat.

bobbym · 2011-09-20 22:21:11

Hi;

I am getting confused, are you saying that 30 and 60 quarts is wrong for this question?

Type A cream is 18% butterfat and type B cream is 24% butterfat. Set up a table to help you determine how many quarts of each type of cream must be used to create a 90 quart mixture that is 22% butterfat.

Bob · 2011-09-20 22:40:55

hi zee-f

Your new answer for 17 = F

This is correct!

Just looking at 20. Arrh. I see you've had 'D' marked correct so no problem there.

Now to look at 19.

No I didn't make it F.

Show your working and we'll be able to find what's going wrong.

Bob

Last edited by Bob (2011-09-20 22:46:39)

bobbym · 2011-09-20 22:48:33

Hi;

I am not getting that.

30 quarts at .18 = 5.4 quarts of cream in there.

60 quarts at .24 = 14.4 quarts of cream in there.

19.8 quarts of cream in 90 total quarts is .22

Answer D.

http://www.algebra.com/algebra/homework … 45483.html

Bob · 2011-09-20 22:54:14

hi bobbym,

We're not talking about the same question. It came in two parts:

17 Identify the correct table to help solve the question.

18. Now find the answer.

Zee-f and you did 18 without ever doing 17 and we all agree (teacher too) with the answer, D.

But she still had to find the right table for 17. She's done that now and got F marked correct for that.

So, there's just 19 to sort out. I'm not surprised it's causing difficulty; the wording is horrible. I had to read and re-read it several times before I understood what was being asked.

And the numbers are nasty too.

But I have arrived at an answer that makes sense and it's not hers.

Bob

Last edited by Bob (2011-09-20 22:55:05)

bobbym · 2011-09-20 22:56:01

Hi;

Oh I see, thanks for clearing that up.

Bob · 2011-09-20 22:58:35

I see you've gone back to the flashing thingy.

There was a young man masquerading as you yesterday.

Bob

bobbym · 2011-09-20 23:00:31

Yes, he was. He will get what he deserves.

zee-f · 2011-09-21 00:20:51

i really hate this lesson so number 19 what is asking for should i multiply 5.5% by the 40.0

bobbym · 2011-09-21 00:30:02

Hi;

19. A certain chain saw requires a fuel mixture of 5.5% oil and the remainder gasoline. How many liters of 2.5% mixture and how many of 9% mixture must be combined to produce 40.0 liters of 5.5% mixture?
A 12 4/23 liters of 2.5% and 28 19/23 liters of 9%
B 28 19/23 liters of 2.5% and 12 4/23 liters of 9%
C 21 liters of 2.5% and 18 liters of 9%
D 18 6/13 liters of 2.5% and 21 7/13 liters of 9%
E 21 7/13 liters of 2.5% and 18 6/13 liters of 9%
F 18 7/13 liters of 2.5% and 21 6/13 liters of 9%

I did it the same way I did 17. I get E

zee-f · 2011-09-21 00:41:03

x = liters of 2.5% mixture. then (40 - x) = liters of 9% mixture.
oil from 2.5% mixture + oil from 9% mixture = oil in 5.5% mixture

ok am confused

Bob · 2011-09-21 00:41:24

hi

OR using a table. See below.

Bob

ps. Dear reconsideryouranswer, Hope this isn't confusing you. Just in case: the dots are decimal points and the times sign is a times sign.

Last edited by Bob (2011-09-21 00:45:35)

zee-f · 2011-09-21 00:51:29

2.5x + 9(40 + -1x) = 5.5 * 40
2.5x + (360 + -9x) = 5.5 * 40
360 + -6.5x = 220

-6.5x = 220 + -360
-6.5x = -140
x = 21.53846154

ok then what... omg this lesson its all getting confusing uhhhhh

Bob · 2011-09-21 00:57:00

Hi

No. That's it. You've got answer E the same as bobbym and me. But you've written it as a decimal not a fraction.

Take 7/13, convert to a decimal by 7 divided by 13 and you get 0.5384... There you go. You've done it!! :)

Bob

zee-f · 2011-09-21 00:59:52

really omg thank you sooo soooo much

bobbym · 2011-09-21 01:07:26

Hoo Hah! As the great Al Pacino would say. Now tell me the good news, aliens have abducted your teacher so there will be
no more of these questions!

zee-f · 2011-09-21 01:28:47

lol i have one more lesson to complete my algebra course for grade 9 am sooooooooo happy thank you guys sooo sooosooooooooooosoooooo muchhhhh

bobbym · 2011-09-21 01:30:44

Hi;

Okay, but make the problems easy. Do you like math?

zee-f · 2011-09-21 01:40:31

hey

there just review questions lol yeah i love math but i hated the mixer word problem lesson

Math Is Fun Forum

#76 2011-09-20 10:54:11

Re: Solving Rational Equations

#77 2011-09-20 10:55:37

Re: Solving Rational Equations

#78 2011-09-20 10:56:47

Re: Solving Rational Equations

#79 2011-09-20 10:57:47

Re: Solving Rational Equations

#80 2011-09-20 19:32:09

Re: Solving Rational Equations

#81 2011-09-20 22:18:22

Re: Solving Rational Equations

#82 2011-09-20 22:20:34

Re: Solving Rational Equations

#83 2011-09-20 22:21:11

Re: Solving Rational Equations

#84 2011-09-20 22:40:55

Re: Solving Rational Equations

#85 2011-09-20 22:48:33

Re: Solving Rational Equations

#86 2011-09-20 22:54:14

Re: Solving Rational Equations

#87 2011-09-20 22:56:01

Re: Solving Rational Equations

#88 2011-09-20 22:58:35

Re: Solving Rational Equations

#89 2011-09-20 23:00:31

Re: Solving Rational Equations

#90 2011-09-21 00:20:51

Re: Solving Rational Equations

#91 2011-09-21 00:30:02

Re: Solving Rational Equations

#92 2011-09-21 00:41:03

Re: Solving Rational Equations

#93 2011-09-21 00:41:24

Re: Solving Rational Equations

#94 2011-09-21 00:51:29

Re: Solving Rational Equations

#95 2011-09-21 00:57:00

Re: Solving Rational Equations

#96 2011-09-21 00:59:52

Re: Solving Rational Equations

#97 2011-09-21 01:07:26

Re: Solving Rational Equations

#98 2011-09-21 01:28:47

Re: Solving Rational Equations

#99 2011-09-21 01:30:44

Re: Solving Rational Equations

#100 2011-09-21 01:40:31

Re: Solving Rational Equations

Board footer