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How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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29 Mar 2015, 12:25
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How many different pairs of numbers (s, t) such that s = 3t can be obtained if s and t are selected from the set of number {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} A. 1 B. 2 C. 3 D. 4 E. 5 This should be a really easy exercise, but I only see 3 pairs and the answer key says the right answer is 4!
I can only think of s=3, t=1 s=6, t=2 s=9, t=3
What would the missing pair be???
Thank you!
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Last edited by Bunuel on 30 Mar 2015, 02:31, edited 1 time in total.
Renamed the topic and edited the question.



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Re: How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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29 Mar 2015, 19:14
Hi inesllopart, This question has a bit of 'quirky' wording to it. When the prompt states "how many different pairs of numbers (S,T) ....", it does NOT mean that S and T have to be different numbers. It's asking for the number of different PAIRS. Given the rest of the language in the prompt, (0,0) is one of the possible pairs. The questions that you'll face on the Official GMAT are carefully worded to remove any of the odd wording and "bias" that could occur on the part of the reader, so this 'issue' shouldn't show up on Test Day. GMAT assassins aren't born, they're made, Rich
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Re: How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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30 Mar 2015, 03:50
inesllopart wrote: How many different pairs of numbers (s, t) such that s = 3t can be obtained if s and t are selected from the set of number {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} A. 1 B. 2 C. 3 D. 4 E. 5 This should be a really easy exercise, but I only see 3 pairs and the answer key says the right answer is 4!
I can only think of s=3, t=1 s=6, t=2 s=9, t=3
What would the missing pair be???
Thank you! Given s=3t t can take 0,1,2,3 and so s = 0,3,6,9 4 such pairs can be formed. answer D
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Re: How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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31 Mar 2015, 12:27
[quote="inesllopart"]How many different pairs of numbers (s, t) such that s = 3t can be obtained if s and t are selected from the set of number {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} A. 1 B. 2 C. 3 D. 4 E. 5 s = 3t. So, s/3 = t That means s is divisible by 3. Only 0, 3, 6, 9 are divisible by 3. Hence option (D).  Optimus Prep's GMAT On Demand course for only $299 covers all verbal and quant. concepts in detail. Visit the following link to get your 7 days free trial account: http://www.optimusprep.com/gmatondemandcourse



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Re: How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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23 Oct 2017, 23:25
inesllopart wrote: How many different pairs of numbers (s, t) such that s = 3t can be obtained if s and t are selected from the set of number {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} A. 1 B. 2 C. 3 D. 4 E. 5 This should be a really easy exercise, but I only see 3 pairs and the answer key says the right answer is 4!
I can only think of s=3, t=1 s=6, t=2 s=9, t=3
What would the missing pair be???
Thank you! The pairs can be {0,0}, {3,1} , {6,2}, {9,3} So total 4 pairs .. Answer D
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Re: How many different pairs of numbers (s, t) such that s = 3t can be obt [#permalink]
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24 Oct 2017, 00:54
since s = 3t => s can take one of 4 values: 0,3,6,9 & t can take 1 of 4 values = 0,1,2,3 Then we can form 4 pairs => answer D




Re: How many different pairs of numbers (s, t) such that s = 3t can be obt
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