# Different logic

1. Jun 8, 2014

1. The problem statement, all variables and given/known data
$\frac{1}{2}(5)=3$ , based on this logic, what is $\frac{1}{3}(10)$?

3. The attempt at a solution
In real life, $\frac{1}{2}(5)=2.5$ so
2.5 --> 3
Just like that, $\frac{1}{3}(10)=\frac{10}{3}$
so
2.5 --> 3
10/3 -->x

Cross multiply---
x=4
I am not very sure whether this is correct or not. I don't know what logic this question assumes. Proportion or addition?

2. Jun 8, 2014

### micromass

You haven't described a logic yet. You have to state all the rules you are using. Just by stating that $5/2=3$ doesn't get you anywhere, because the only thing it implies is that $5/2=3$, nothing else.

3. Jun 8, 2014

I don't understand

4. Jun 8, 2014

### micromass

Can you list all the rules (axioms) of your system?

5. Jun 8, 2014

Are you asking what I assumed?
We know that(From the question) $\frac{5}{2}=3=2.5$ So what I assumed is
$3=k2.5$ | $k=1.2$
Let $i$ be the false(Logic of the question) value and $r$ be the true value
Then $i=1.2r$
So $x=1.2 \times \frac{10}{3}$
$x=4$

6. Jun 8, 2014

### CAF123

5/2 = 3 is simply a statement - there is nothing you can extrapolate from this to answer your question. The real number system obeys a set of axioms, so similarly there must exist a set of axioms that your system has to adhere to. Was there more given in the question or in an earlier exercise perhaps?

7. Jun 8, 2014

That is the problem. I wrote exactly as the question was written. This is not an exercise, I saw this from the internet.

So the question cannot be answered without knowing what rules it obeys();?

8. Jun 8, 2014