Problem Solving

If [x] is the greatest integer less than or equal to x,
what is the value of [-1.6] + [3.4] + [2.7] ?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

Hi - You might want to say in your post that this is a GMAT Prep Test question. That way people who are saving the GMAT Prep Tests for later don't see the question beforehand.

its not a gmat prep q!

are you sure? I rem getting this question wrong in one of the practice tests I took.

beatthegmatinsept wrote:are you sure? I rem getting this question wrong in one of the practice tests I took.

yes sir,

this is q. 143 in og

Is the answer A 3?

(-2) + (3) + (2) = 3??

HPengineer wrote:Is the answer A 3?

(-2) + (3) + (2) = 3??

yes it is....please explain! thanks

Well basically i thought of that [] as a function

And question states that any value placed in that function spits out the greatest integer less then the value placed in the function..


For instance if they plugged [3.9] the greatest integer less then that value is 3.0...

Not sure if this logic is correct but it gave the right answer luckily

Gurpinder wrote:If [x] is the greatest integer less than or equal to x,
what is the value of [-1.6] + [3.4] + [2.7] ?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

Break each down 1 by 1. Since none of these are integers, they must the the greatest int less than the number

What is the greatest integer less than -1.6?
-2 (remember, -2 is less than -1.6, -1 is greater than -1.6)

3 is the greatest less than 3.4


2 is the greatest less than2.7.

3+2-2=3

3 (A) it is as explained above....

Gurpinder wrote:If [x] is the greatest integer less than or equal to x,
what is the value of [-1.6] + [3.4] + [2.7] ?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

imagine a number line contains these numbers... what this fuction says is... that our interger should be on or to the left of the given number...

so [-1.6] would have -2 to its left
[3.4] would have 3
[2.7] would have 2

summation of -2 +3 +2 = 3
answer is A

Great explanation, arora! One thing I want to chime in with - this is a fantastic example of just a pure "GMAT Problem". It's really easy for people to see a problem that only includes arithmetic (in this case addition) and see it as "easy" or even "too easy", and then start to think that their score is tanking because the question was too easy.

When you see questions that look easy, take a few seconds to try to find the difficulty. Ultimately, there are two main reasons that you could see an "easy" question on test day even if you are doing well:

1) It's an experimental question and they need to prove that someone scoring at your high level does, indeed, always get it right.

2) It's not an easy question, and you're just missing the difficulty.

#2 is a killer - the GMAT loves to sneak its difficulty past you without your ever knowing. So if a question looks "easy", look for the difficulty. What might you be missing? Often what you're missing is embedded in the definition of a term. Here, it's:

the greatest integer LESS THAN or EQUAL TO x.

The difficulty? "LESS THAN" gets us looking for a smaller absolute value. Mentally, we just assume that 1 is less than 2, negative sign be damned. But -1 is GREATER than -1.6. We need to, as arora mentioned, go left on the number line.

On a question like this, you should really be able to not just correctly round down to -2 + 3 + 2 = 3, but also be able to check off the "difficulty" and say "it's 3, but they want me to think 4 because of the negative". Much of success on this test comes from your ability to think like the testmaker - to know where the traps are coming from and which concepts the GMAT likes to use to set them. Even if this question was "easy" to you, look for where the difficulty lies and you'll get a better feel for how to take this test overall.

Thanks Brian. Following is what I got in the email from BTG. I solved it for '3' and then kept on looking for that option in answer thinking thta there is some difficult parat I am missing (of course after coming here I found that choices were wrong)

In any case, agree with you - there are times when Q is referred to as ADVANCED and it is straight forward and then there are timess when it looks daunting and explanation makes it look so simple. It is all in how you approach the Q and that is why GMAT is trying to test (my tutor's words not mine )

If [x] is the greatest integer less than or equal to x, what is the value of [-1.6] + [3.4] + [2.7]?
(A) 12
(B) 9
(C) 15
(D) 14
(E) 13

arora007 wrote:

Gurpinder wrote:If [x] is the greatest integer less than or equal to x,
what is the value of [-1.6] + [3.4] + [2.7] ?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

imagine a number line contains these numbers... what this fuction says is... that our interger should be on or to the left of the given number...

so [-1.6] would have -2 to its left
[3.4] would have 3
[2.7] would have 2

summation of -2 +3 +2 = 3
answer is A

also @Brian, the same logic here:
x=i {i is integer}
x=< 'x {only integer part!}
[-1.6] + [3.4] + [2.7] --> -2=<[-1.6], 3=<[3.4], 2=<[2.7] --> -2+3+2=3

Greatest values less than or eqaul to [-1.6] = -2
Greatest values less than or eqaul to [3.4] = 3
Greatest values less than or eqaul to [2.7] = 2

so the value = -2+3+2= 3