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How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Sep 2012, 04:04
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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Sep 2012, 04:04
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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Sep 2012, 04:15
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1< 5n +5 < 25

-> -4<5n<20

-> -.8<n<4

Four integers are possible

Answer B

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Sep 2012, 07:43
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Bunuel wrote:

How many integers n are there such that 1< 5n +5 < 25? (A) Five (B) Four (C) Three (D) Two (E) One

expression can be split into two equations:

1 < 5n + 5 ==> 5n > -4 ==> n > -0.8

5n + 5 < 25 ==> 5n < 20 ==> n < 4

now between -0.8 and 4(excluding) , there exist 4 integers, viz. 0, 1, 2, 3

hence B

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
28 Sep 2012, 03:55

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
10 Dec 2012, 03:23

1 < 5n +5 < 25 1 - 5 < 5n + 5 - 5 < 25 -5 -4 < 5n < 20 -4/5 < n < 4 <===(-1)=-4/5

=(0)=(1)=(2)=(3)= (4)==>

x-axis Answer: B

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
11 Dec 2012, 03:14

is it correct? 5*1+5=10 5*2+5=15 5*3+5=20 5*4+5=25 -->n=4

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
11 Dec 2012, 03:56

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How many integers of N are there? [#permalink ]
24 Jun 2013, 03:45

How many integers N are there such that: 1<5n+5<25 ? a. 5 b. 4 c. 3 d. 2 e. 1

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Re: How many integers of N are there? [#permalink ]
24 Jun 2013, 03:49

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Jun 2013, 04:06

Bunuel wrote:

SOLUTION How many integers n are there such that 1< 5n +5 < 25? (A) Five (B) Four (C) Three (D) Two (E) One1< 5n +5 < 25 --> subtract 5 from each part: -4<5n<20 --> divide by 5 each part: -\frac{4}{5}<n<4 . In this range there are 4 integers: 0, 1, 2, and 3. Answer: B.

why is it not -1, 0, 1, 2, 3 ?

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
24 Jun 2013, 04:12
Rs1991 wrote:

Bunuel wrote:

SOLUTION How many integers n are there such that 1< 5n +5 < 25? (A) Five (B) Four (C) Three (D) Two (E) One1< 5n +5 < 25 --> subtract 5 from each part: -4<5n<20 --> divide by 5 each part: -\frac{4}{5}<n<4 . In this range there are 4 integers: 0, 1, 2, and 3. Answer: B.

why is it not -1, 0, 1, 2, 3 ?

Because -1 is LESS than -4/5, and n must be more than -4/5.

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Re: How many integers n are there such that 1< 5n +5 < 25? [#permalink ]
05 Sep 2013, 22:18
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A table showing values of 5n+1 for various values of n. Just need to note the constraint that 1<5n+5<25 (valid values are in green, invalid in red) and count how many valid numbers there are for n.

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Re: How many integers n are there such that 1< 5n +5 < 25?
[#permalink ]
05 Sep 2013, 22:18