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maximum will be 5.. you dont require both the multiplicatin to be negative for entire equation to be negative... any one a or b can be negative to make ab negative and it can still be more(away from 0) than the multiplication of 4 other -ve numbers... actually by writing minimum required as 1 out of 6,you are actually meaning 5 out of 6 also possible as you will see 5 or 1 will give you same equation.. ans D
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maximum will be 5.. you dont require both the multiplicatin to be negative for entire equation to be negative... any one a or b can be negative to make ab negative and it can still be more(away from 0) than the multiplication of 4 other -ve numbers... actually by writing minimum required as 1 out of 6,you are actually meaning 5 out of 6 also possible as you will see 5 or 1 will give you same equation.. ans D

Crap. Yeah, thanks.

Funny part is I had considered this option when I read the question but messed up the execution. Made a mental note of slowing down. :D

If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is the maximum number of integers that can be negative?

A. 2 B. 3 C. 4 D. 5 E. 6

Kudos for a correct solution.

The number can be negative in following conditions: 1) If ab is a bigger negative number than cdef => Both a & b cannot be negative at a time. 2) If cdef is a bigger negative number than ab => All four c, d, e & f cannot be negative at a time

Let one of a & b be negative and let all 4 of c, d, e & f be negative. So, ab will be negative and cdef will be positive but their sum will be negative. Hence maximum 5 can be negative. Hence option (D).

Concentration: General Management, Entrepreneurship

GMAT 1: 670 Q44 V38

Re: If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is [#permalink]

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31 Mar 2015, 19:49

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Originally I chose E but now I changed my mind! I ignored that the sum of the numbers had to be under zero, and tried to make the number positive. Now I think the answer is D --

I put in values to try and make it work:

25 * (-1) + (-1 * -2 * -3 * -4) = -25 + 24 = -1

That's 5 negative numbers that create a value under 1. one more value were to have been positive, the numbers summed up would not be less than 1. Silly mistake I made originally.

Re: If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is [#permalink]

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02 Apr 2015, 02:10

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Bunuel wrote:

If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is the maximum number of integers that can be negative?

A. 2 B. 3 C. 4 D. 5 E. 6

Kudos for a correct solution.

looking at the eqn: (ab + cdef) < 0

In order for the sum of two terms to be -ve, one term has to be -ve for sure. With this mind, we can build mutliple scenarios. To restrict time take to solve this problem assume the same small integers for all unkowns.

So should the question rephrased as the products of the integers ... .

Or we can make the assumption that when we find similiar questions during the GMAT exam, we should just treat it as multiple of products?

If cdef were a 4-digit number if would have been mentioned explicitly. Without that, cdef can only be c*d*e*f since only multiplication sign (*) is usually omitted.
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If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is [#permalink]

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23 Aug 2017, 15:18

Bunuel wrote:

If a, b, c, d, e and f are integers and (ab + cdef) < 0, then what is the maximum number of integers that can be negative?

A. 2 B. 3 C. 4 D. 5 E. 6

Kudos for a correct solution.

To achieve negative result here with maximum number of negative integers, we can't use six. An even number of negative factors yields positive. Six negative factors "eat up" all the individual terms.

Five negative factors, however, will work.

Maximize and minimize

1. Maximize the number of negative factors in (cdef): there can be three. Odd number of negative factors = negative product.

2. Maximize negative factors by two more. Make both a and b negative, but minimize their positive product's absolute value.

Make c, d, and e negative, and for ease, keep them small. Let f be the one positive number. Make it large so that |(cdef)| is > (ab).

Result is a small positive number plus a larger negative number, which yields a negative.

3. Let a, b, c, d, and e = -1 Let f = 20

(-1)(-1) + (-1)(-1)(-1)(20) =

1 + (-20) = 1 - 20 = -19

4. Alternatively, make all but a or b negative, and one number large because: -- if one term in (ab) is negative, and -- the absolute value of (ab) is greater than (cdef) -- the result is a very small negative number (far to the right on the number line) plus a smaller positive number, such that -- sum of terms with those properties is less than 0.

Let b, c, d, e, and f = -1 Let a = 20

(20)(-1) + (-1)(-1)(-1)(-1) = -20 + 1 = -19

The maximum number of negative factors possible for this expression is 5