This question may be very simple for most of you, but everyone in my study group got different answers please help!!

Simplify:

28 - 9 and 21/35

I got 9 and 3/5 as my answer.

Printable View

- Oct 13th 2007, 05:17 PMJason29Help with a pre-algebra question
This question may be very simple for most of you, but everyone in my study group got different answers please help!!

Simplify:

28 - 9 and 21/35

I got 9 and 3/5 as my answer. - Oct 13th 2007, 05:29 PMBen Tillman
For this one: 28 - 9

If the problem was 28 - 8, would you agree with me that the answer would be 20? So now if I take one more away, that is 28 - 9, I should have 19 right?

When simplifying ones like 21/35, see if you can see a common factor in the numerator and denominator. I see a 7 (maybe there are more, but we can deal with them one at a time), that is,

$\displaystyle \frac{21}{35} = \frac{7 \times 3}{7 \times 5}.$

Now, you should be able to convince yourself that 7/7 = 1. So our fraction becomes

$\displaystyle \frac{7 \times 3}{7 \times 5} = 1 \times \frac{3}{5} = \frac{3}{5}.$

So your second answer looks good. As an additional note, since 3 and 5 are both prime numbers, we can instantly say this can not be simplified any further.

Hope that helps. - Oct 13th 2007, 05:38 PMJason29thanks
Appreciate your help, thats the answer I got as well.

- Oct 13th 2007, 11:31 PM~V~9 and 3/5
Working this problem out, I do not get 9 3/5 as an answer. I'm in the same class as Jason29 though, so I could be way off base here. Anyway, the answer I keep coming up with is 18 2/5. :confused:

Anybody else have input on this problem?

Uh oh,

~V~ - Oct 13th 2007, 11:43 PMJhevon
if the problem is $\displaystyle 28 - 9 \frac {21}{35}$

then you are correct. the answer is $\displaystyle 18 \frac 25$ or, as i would prefer to write, $\displaystyle \frac {92}5$, but for some reason, writing improper fractions is a sin at this level, i think they are neater - Oct 13th 2007, 11:49 PM~V~Jhevon~
Phew! Thanks for your input! This quiz was already submitted, but now I know the answer I gave is correct.

Relieved(Whew),

~V~ - Oct 13th 2007, 11:52 PMJason29
I just tried the problem again and this time I got the same answer as V. Thanks for keeping me honest!!!

- Oct 14th 2007, 12:04 AMJhevon
- Oct 14th 2007, 12:09 AMBen Tillman
Oops. Sorry, I thought you were asking two separate questions.

- Oct 14th 2007, 12:12 AMJhevon
- Oct 14th 2007, 12:18 AMBen Tillman
Actually I thought it was a typo (dropped the 1), so I just went through it anyway.

Sorry again!