How is $\frac{4\times 3+5\times 6}{18\times -22} = 3$?

Question

I was preparing for civil services tests and recently came across this question in a book.

Its answer is option C as given in that book.

I have tried to solved it by following DMAS rule and also not following DMAS rule, but I could not get it equal to 3.

How is this possible?

Whoever composed this problem should have their math license revoked. — Jyrki Lahtonen, May 14 '18 at 06:19
I am studying formal languages in computer science and the only part of this expression that I think would be problematic for a basic recursive definition of Arithmetic Expressions is the $18 * -22$ part since -22 should be in brackets, otherwise the denominator should evaluate the multiplications first I believe. — IntegrateThis, May 14 '18 at 06:20
The expression is of course not invalid, but the answer is not in the choices: it's $$-\dfrac{7}{66}$$ — Jean-Claude Arbaut, May 14 '18 at 06:24
@Jean-ClaudeArbaut It IS invalid, the signs "x" and "-" are never allowed to occur in a row. The parenthesis are missing. — Peter, May 14 '18 at 06:25
Ah, I did't think about that, as most programming languages would accept this. Thanks. — Jean-Claude Arbaut, May 14 '18 at 06:27
@Jean-ClaudeArbaut This is correct, apparently to support lazy or careless users :) — Peter, May 14 '18 at 06:28

score 3 · Accepted Answer · answered May 14 '18 at 06:21

3

$$\frac{4\times 3+5\times 6}{18\times 2 -22}=\frac{42}{14}=3$$ So the original expression is probably a typo for the above.

answered May 14 '18 at 06:21

Angina Seng

user · Answer 2 · 2018-05-14T06:25:58.893

1

We have

$$\frac{4\cdot 3+5\cdot 6}{18\cdot -22}=-\frac{42}{396}=-\frac{7}{66}$$

maybe the original problem was

$$\frac{4\cdot 3+5\cdot 6}{18-(2^2)}=\frac{42}{14}=3$$

edited May 14 '18 at 06:25

answered May 14 '18 at 06:18

user

@JyrkiLahtonen I don't know the level of the asker, I have no prejudices about this, simply I try to give a good help for the posed OP. That's all. – user May 14 '18 at 06:24
1

Wow! Well done with finding an expression that matches the answer! – Matti P. May 14 '18 at 06:29
@MattiP. Thanks, also Lord Shark has found a good explanation. – user May 14 '18 at 06:54

2 Answers2