How many integers n are there such that
1 < 5n + 5 < 25 ?
(A) Five
(B) Four
(C) Three
(D) Two
(E) One
1 < 5n < 20
1,2,3 only matches!!
[spoiler]IMO:C OA:B[/spoiler]
Integer N
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When you subtract 5, you have to subtract it from every part of the inequality. It should be:
1<5n+5<25
-4<5n<20
-4/5<n<4
so n could be 0,1,2, or 3
1<5n+5<25
-4<5n<20
-4/5<n<4
so n could be 0,1,2, or 3
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-4 < 5n < 20, -4/5 < n < 4, we have 0,1,2,3
gmatblood wrote:How many integers n are there such that
1 < 5n + 5 < 25 ?
(A) Five
(B) Four
(C) Three
(D) Two
(E) One
1 < 5n < 20
1,2,3 only matches!!
[spoiler]IMO:C OA:B[/spoiler]
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- neelgandham
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1 < 5n + 5 < 25
You can also substitute in this case !
If 5n + 5 = 0 then n = -1, So we can start from 0 which is the immediate neighbor of -1
n=0 5n + 5 =5
n=1 5n + 5 =10
n=2 5n + 5 =15
n=3 5n + 5 =20
n=4 5n + 5 =25 Stop here, this doesn't satisfy !
so Answer = [spoiler]B) 4[/spoiler]
You can also substitute in this case !
If 5n + 5 = 0 then n = -1, So we can start from 0 which is the immediate neighbor of -1
n=0 5n + 5 =5
n=1 5n + 5 =10
n=2 5n + 5 =15
n=3 5n + 5 =20
n=4 5n + 5 =25 Stop here, this doesn't satisfy !
so Answer = [spoiler]B) 4[/spoiler]
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Simplifying the inequality, we have:gmatblood wrote:How many integers n are there such that
1 < 5n + 5 < 25 ?
(A) Five
(B) Four
(C) Three
(D) Two
(E) One
1 < 5n + 5 < 25
-4 < 5n < 20
-4/5 < n < 4
The integers that are greater than -4/5 and less than 4 are 0, 1, 2, and 3. Thus, there are 4 integers that satisfy the inequality 1 < 5n + 5 < 25.
Answer: B
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