Solve June's Problem: Monthly Allowance of \$290?

[wailingkoh]

Hi
I have a problem sum question. I have attempted it but I think that my answer is incorrect. Please help.

June, Dan spent 20% of his monthly income on food and \$18 less on transport than on food. He spent \$10 more on phone bills than on food and saved the remaining \$108. What was his monthly allowance?

My answer is \$290

Please advice

 

[MarkFL]

Hi
I have a problem sum question. I have attempted it but I think that my answer is incorrect. Please help.

June, Dan spent 20% of his monthly income on food and \$18 less on transport than on food. He spent \$10 more on phone bills than on food and saved the remaining \$108. What was his monthly allowance?

My answer is \$290

Please advice

First, because we use dollar signs as tags for $\LaTeX$, if you want to use plain dollar signs in your text, precede them with a backslash.

Okay, now I get a different answer to this question than you did, but without seeing your work I have no idea where you may have gone wrong (assuming I am right). Can you post what you did?

 

[wailingkoh]

First, because we use dollar signs as tags for $\LaTeX$, if you want to use plain dollar signs in your text, precede them with a backslash.

Okay, now I get a different answer to this question than you did, but without seeing your work I have no idea where you may have gone wrong (assuming I am right). Can you post what you did?

Hi,
Thanks for you reply. Yes I did post my my working in the problem sum thread. In photo form :)

 

[wailingkoh]

Hi,
Thanks for you reply. Yes I did post my my working in the problem sum thread. In photo form :)

I got $250 using algebra

 

[MarkFL]

Hi,
Thanks for you reply. Yes I did post my my working in the problem sum thread. In photo form :)

You need to post your working in the thread in which you are asking for help...you certainly shouldn't expect people to have to locate another thread (or even know it is in another thread) to find your work. And I do recall that thread, and I found those small images of hand-written work too difficult to read. You may recall I stated as much in that thread. :D

You are to be commended for having posted your work, and I don't want you to think I am completely disregarding that fact. I am just offering suggestions on how to make it easier for people to help you, which will ensure you get more timely help. I would suggest either making your images somewhat larger or even better to type your work (I would only upload images of supporting diagrams). If you are uploading an image of handwritten work, make certain is it neat and legible. :D

I got $250 using algebra

Yes, that's what I got too, and here's what I did:

Let:

$I$ be the monthly income.

$F=0.2I$ is the monthly amount spent on food.

$T=F-18=0.2I-18$ is the monthly amount spent on transport.

$P=F+10=0.2I+10$ is the monthly amount spent on phone bills.

Now, we are told that the remainder (what's left after those monthly expenses) is \$108. And so we may write:

\(\displaystyle I-(F+T+P)=108\)

\(\displaystyle I-(0.2I+.2I-18+0.2I+10)=108\)

\(\displaystyle I-(0.6I-8)=108\)

\(\displaystyle I-0.6I+8=108\)

\(\displaystyle 0.4I=100\)

\(\displaystyle \frac{5}{2}\cdot0.4I=\frac{5}{2}\cdot100\)

\(\displaystyle I=250\)