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Today Rose is twice as old as Sam and Sam is 3 years younger
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14 Oct 2008, 17:04
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Today Rose is twice as old as Sam and Sam is 3 years younger than Tina. If Rose, Sam, and TIna are all alive 4 years from today, which of the following must be true on that day? 1. Rose is twice as old as Sam. 2. Sam is 3 years younger than Tina. 3. Rose is older than Tina. OPEN DISCUSSION OF THIS QUESTION IS HERE: todayroseistwiceasoldassamandsamis3yearsyounger131477.html== Message from the GMAT Club Team == THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.



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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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15 Oct 2008, 01:44
I encountered this problem and I swore up and down the answer was 2 & 3, but the book says it is just 2, I don't get it.
Today Rose is twice as old as Sam and Sam is 3 years younger than Tina. If Rose, Sam, and TIna are all alive 4 years from today, which of the following must be true on that day?
1. Rose is twice as old as Sam. 2. Sam is 3 years younger than Tina. 3. Rose is older than Tina.[/quote]
today
t ( tina) , t3 ( sam) ,2(t3) ( rose)
4 years from now
t+4 ( tina) , t+1 ( sam), 2t2( rose)
from 1
is 2(t1) = 2( t+1)...........no
from 2
is t+1+3 = t+4........yes
from 3
is
2t2> t+4
ie: is t>6..........we can never know..........no
thus only 2 is possible



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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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15 Oct 2008, 05:41
Rosa and Tina can be a same age
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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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15 Oct 2008, 07:36
Substitute numbers, things become easier.



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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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23 Sep 2011, 11:16
best to substitute or express in terms of 1 variable to make calculation quicker and easier and you won't have to solve lots of simultaneous equations with multiple variables.
so...
approach 1: use a table to organise the info given >
today  + 4yrs  R 6  10 S 3  7 T 6  10
now you can prove/disprove each statement.
Approach 2: use a table again, but use variables instead of numbers (I prefer doing this, makes things easier and neater)
today  + 4yrs  R 2S  2S + 4 S S  S + 4 T S+3  (S + 3) + 4 = S + 7
1. Is 2S + 4 equal to 2(S+4)? No. 2. Is Sam 3 years younger than Tina? Yes... (S + 7) (tina's age in 4 year)  3 = S + 4 (Sam's age in 4 years) 3. Is Rose older than Tina? Not necessarily. Answer = No. I said not necessarily because if S = 2, then in 4 years R = 12 and T = 9 ... BUT IF s = 1, then in 4 years, R = 5 and T = 8... This is kind of like a D.S. question actually if you solve using algebra...



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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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30 Jul 2017, 20:10
TrillTalk wrote: Today Rose is twice as old as Sam and Sam is 3 years younger than Tina. If Rose, Sam, and TIna are all alive 4 years from today, which of the following must be true on that day? 1. Rose is twice as old as Sam. 2. Sam is 3 years younger than Tina. 3. Rose is older than Tina. Notice that we are asked which of the following MUST be true not COULD be true. Stem says that "Sam is 3 years younger than Tina" which naturally be exactly so ANY number of years from today. So, II is always true. Which means that the answer is B (II only), D (I and II only) or E (II and III only). Analyze options I and III I. Rose is twice as old as Sam. III. Rose is older than Tina Now, if today Rose is 4 years old, Sam is 2 years old and Tina is 5 years old then after 4 years Rose will be 8 years old, Sam is will be 6 years old and Tina will be 9 years old, so neither option I nor option III holds true. Answer: B (II only). OPEN DISCUSSION OF THIS QUESTION IS HERE: todayroseistwiceasoldassamandsamis3yearsyounger131477.html== Message from the GMAT Club Team == THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.
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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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13 Oct 2018, 05:15
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Re: Today Rose is twice as old as Sam and Sam is 3 years younger
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