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R is the set of positive odd integers less than 50, and S is

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R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 08 Mar 2011, 06:52
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R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R. How many elements does the intersection of R and S contain ?

(A) None
(B) Two
(C) Four
(D) Five
(E) Seven
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Re: p/s sets  [#permalink]

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New post 08 Mar 2011, 07:12
squares < 50 {1,4,9,16,25,36,49 }
S = {1,9,25,49}
R = {1,3,.....49}
Hence C.

Lolaergasheva wrote:
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R. How many elements does the intersection of R and S contain ?
(A) None
(B) Two
(C) Four
(D) Five
(E) Seven
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Joined: 02 Sep 2009
Posts: 49303
Re: p/s sets  [#permalink]

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New post 08 Mar 2011, 07:18
1
gmat1220 wrote:
squares < 50 {1,4,9,16,25,36,49 }
S = {1,9,25,49}
R = {1,3,.....49}
Hence C.

Lolaergasheva wrote:
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R. How many elements does the intersection of R and S contain ?
(A) None
(B) Two
(C) Four
(D) Five
(E) Seven


R is the set of positive odd integers less than 50: R={1, 3, 5, ..., 49}
S is the set of the squares of the integers in R: S={1^2, 3^2, 5^2, ..., 49^2}={1, 9, 25, 49, 81, 121, ..., 2401}

The intersection of R and S contains the odd perfect squares which are less than 50: 1^2=1, 3^2=29, 5^2=25, and 7^2=49.

Answer: C.
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Re: p/s sets  [#permalink]

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New post 21 Dec 2012, 19:38
1
simple question, but let's solve it in a GMAT way - with out writing any numbers/sets down

Given,
R is set of positive ODD integers < 50
S is set of squares of integers in R

now, we know that all numbers in R are ODD. square of an ODD number is ODD. the qtn is what are the ODD and PERFECT squares < 50. 1, 3,25, and 49...i hope you got what i mean and why i solved this in this way. This is a simple question but solving this question in this way would help us solve 700+ level questions.
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R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 19 Mar 2013, 05:21
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R.
How many elements does the intersection of R and S contain?

A. None
B. Two
C. Four
D. Five
E. Seven
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Re: R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 19 Mar 2013, 05:23
johnwesley wrote:
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R.
How many elements does the intersection of R and S contain?

A. None
B. Two
C. Four
D. Five
E. Seven


Merging similar topics. Please refer to the solutions above.
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

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Re: R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 19 Mar 2013, 05:26
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R.
How many elements does the intersection of R and S contain?

R=1,3,5,7,9,11,13,15...

S=1,9,25,49,81...

Numbers: 1, 9, 25, and 49 are odd integers (less than 50) that are in both sets.

Solution: Four

Answer: C
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Re: R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 23 Jul 2016, 07:25
Lolaergasheva wrote:
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R. How many elements does the intersection of R and S contain ?

(A) None
(B) Two
(C) Four
(D) Five
(E) Seven


R={1,3,5,7,9,11,13,15,17,19,21,..................49}
S={1,4,9,16,25,36,49................ 2401}

Common will only be
\(1^2=1\)
\(3^2=9\)
\(5^2=25\)
\(7^2=49\)

so four elements are common in both set

ANSWER IS C
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Re: R is the set of positive odd integers less than 50, and S is  [#permalink]

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New post 20 Aug 2018, 11:41
Lolaergasheva wrote:
R is the set of positive odd integers less than 50, and S is the set of the squares of the integers in R. How many elements does the intersection of R and S contain ?

(A) None
(B) Two
(C) Four
(D) Five
(E) Seven


Since the a number’s square grows much faster than the number itself, let’s look at the odd perfect squares in S:

1^2 = 1, 3^2 = 9, 5^2 = 25, 7^2 = 49, 9^2 = 81, etc.

We see that, of the numbers in S, 1, 9, 25 and 49 are also in R, so R and S have 4 numbers in common.

Answer: C
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Re: R is the set of positive odd integers less than 50, and S is &nbs [#permalink] 20 Aug 2018, 11:41
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