48÷2(9+3) = ?

Original post by Best Superlative

You've rearranged the problem! :tongue:

The way you've written it is an inferred action, and that's where I think the majority of the incorrect calculations are coming from. Don't alter it, just take it how it is. :tongue:

Or maybe the questioner is an idiot who should've made it clearer? Lets just come to the conclusion that some people will obtain an answer of 2 or 288 but the questioner should've displayed the question with more clarity. I still would take the answer to be 2.

Reply 122

Piecewise

8

Original post by py0alb

48/2(9+3) = poor notation.

Meaningless, in fact.

Reply 123

The reason so many people mistakenly arrive at 2 as the answer is that they are ascribing a false affinity or higher priority to the operation between the 2 and the "(9+3)" and interpreting it as having to be calculated before the division. In fact, between the 2 and the parenthesis is merely an implied multiplication, so the expression is actually:

48/2(9+3) = 48/2x(9+3) = 48/2x12 = 288.

Reply 124

Best Superlative

Original post by DanielleT192

Or maybe the questioner is an idiot who should've made it clearer? Lets just come to the conclusion that some people will obtain an answer os 2 or 288 but the questioner should've displayed the question with more clarity. I still would take the answer to be 2.

The notation is very poor, and it's obviously designed to confuse people by making them process it in an incorrect way. Some people will naturally group the 2(9+3) into one problem unit (whereas the 2 and the (9+3) are units by themselves) and perform that calculation before dividing 48 by the result.

But as a series of operations, I would* say that it's pretty much inarguable (at least in CompSci) that it would process each of the steps in a linear progression according to BIDMAS, i.e. 48 divided by 2 multiplied by 12 = 288.

*I say "would", but the fact that we're arguing about it would seem to suggest that it's up for debate. :tongue:

(edited 13 years ago)

Reply 125

jit987

Original post by DanielleT192

Or maybe the questioner is an idiot who should've made it clearer? Lets just come to the conclusion that some people will obtain an answer of 2 or 288 but the questioner should've displayed the question with more clarity. I still would take the answer to be 2.

Agree

Reply 126

Ice_Queen

17

I thought 2.

I then checked my calculator.

It thinks 2 too.

Reply 127

Original post by Ice_Queen

I thought 2.

I then checked my calculator.

It thinks 2 too.

I'm please to discover that my calculator, a Sharp EL-531H, works correctly and gives 288. Lots of calculators just do simple left to right, which is totally wrong.

Reply 128

booooom

Original post by Hedgeman49

The answer is 288.

Your brain thinks that the answer is 2 because 48/2(3+9) makes the 2(3+9) look "grouped together" and hence bracketed even though it is no more bracketed than the rest of the expression. (I admit that my instant reaction to this was 2 and only when I thought about it further did I realise I was wrong).

You've got/ going to have a masters in maths so im guessing you would know and so 288 would probably be right, although ive always thought ud have to use BIDMAS for these types of calculations, and according to that, the answer is 2. :smile:

Reply 129

james.h

11

It's 288, by BIDMAS. :yep:

This is why it's usually better to go crazy with brackets in public, just to make sure you're not misinterpreted.

Reply 130

Original post by booooom

ive always thought ud have to use BIDMAS for these types of calculations, and according to that, the answer is 2. :smile:

Read my post 127, and I'll bet you'll find you haven't applied it correctly.

Reply 131

HistoryRepeating

BIDMAS is just a useful shorthand for young kids to learn. The actual orders of precedence look like this:

terms inside brackets
exponents and roots
multiplication and division
addition and subtraction

There is no preference between multiplication and division, but you parse then left to right.

Thus it is, indeed 288, but strict application of BIDMAS alone doesnt get you there, you also need to know the left-to-right rule.

(edited 13 years ago)

Reply 132

Mechie

15

Original post by HedonisticMe

you do know they're two entirely different equations?

on the second you'd times by 1/2(9 + 3)...

I know they're different, that's why I wrote them out. It's what the OP asked, and the two different ways it can be interpreted.

Reply 133

xoxAngel_Kxox

21

This is really embarassing given that it's so simple, and I'm 20, but I had to do it twice ha ha. I agree it's 2 now though :smile:

Reply 134

Original post by HistoryRepeating

Are you, and every other idiot in this thread claiming anything other than 2, trolling?

Seriously, are you all really that stupid?

Basic rule of maths that you work from right to left when dealing with operations of the same priority: so it goes brackets first (highest priority) then right to left on the multiplication and division.

I am convinced most people claiming 288 are trolling.

Certainly not! You have to expand the operators first, before executing them - as I demonstrated - then go from left to right. 48 / 2 x 12 is obviously 288, isn't it?

Reply 135

Original post by Gemma :)!

I agree it's 2 now though :smile:

Oh dear!

Reply 136

DanielleT192

Original post by Best Superlative

The notation is very poor, and it's obviously designed to confuse people by making them process it in an incorrect way. Some people will naturally group the 2(9+3) into one problem unit (whereas the 2 and the (9+3) are units by themselves) and perform that calculation before dividing 48 by the result.

But as a series of operations, I would* say that it's pretty much inarguable (at least in CompSci) that it would process each of the steps in a linear progression according to BIDMAS, i.e. 48 divided by 2 multiplied by 12 = 288.

*I say "would", but the fact that we're arguing about it would seem to suggest that it's up for debate. :tongue:

But you're basically saying that 48 divided by 2(12) should be treated as 48 divided by 2 and then multiplied by 12 to obtain the answer of 288 simply because of the arrangement of BODMAS. Multiplication and division are treated equally, as does subtraction and addition and I'm guessing the only reason that BODMAS is spelt that way is to make it easier for people to remember the rule that brackets takes priority in terms of arithmetic equations.

Really, it's the way the question is set out and that is the most important thing. The questioner doesn't expect you to use a calculator to work out this question or have a "computing minded" mode, but use initiative to what you could see. So I still stick to 2, even though it's obvious the question isn't presented well.

Edit: Why the neg reps :s-smilie:

? It's true.

(edited 13 years ago)

Reply 137

SalBhatti