Easy Algebra - Help?

4rch3nemy

I've been so out of the loop, school-wise, that I just can't wrap my head around this stupid easy math. We didn't even do any algebra in this mathematical literacy class, so I'm wondering how I should have figured this out.

There's a 10% discount. You want to spend 100 dollars. What should the bill read prior to the discount?

111.11 is the answer. I just did some guesswork to find it. How could I have found the answer more easily?

100 = x - x0.1 could be one way to do it, but I totally forget how to do this as well. Ugh.

Help?

shadydentist

You're on the right track. Whats x-.01x?

admanb

Erm.

100 = x - 0.1x
100 = 0.9x
x = 100/0.9

physi_marc

Yes, you've got it right. Just solve for x. On the left-hand side you have: x - 0.1x = 1x - 0.1x = (1-0.1)x = 0.9x. So, you end up with:

100 = 0.9x

Remember how to solve for x, now?

Metalbourne

I'm not sure what the question is, but you've answered it yourself:

x is the bill,
.1x is the discount
x-.1x = 100, solve for x.
.9x = 100
x = 100/.9

4rch3nemy

Ah.

I was screwing myself over with my previous algebra lessons (from a long-ass time ago). Why did I not know how to do x - 0.1x?

*facepalm*


Thanks