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Magoosh GMAT Instructor
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In each term of a sequence, 9 is added to get the next term. If the
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20 Mar 2013, 13:18
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In each term of a sequence, 9 is added to get the next term. If the first term is 2, what is the eightyfirst term?
(A) 632 (B) 695 (C) 713 (D) 722 (E) 731For more on sequences, as well as a complete explanation of this question, see: http://magoosh.com/gmat/2012/sequencesonthegmat/Mike
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Mike McGarry Magoosh Test Prep
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Re: In each term of a sequence, 9 is added to get the next term. If the
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20 Mar 2013, 13:35
1rst term + 80 terms = 2 + 9+9+9+9+9+9+9+...+9 (80 times)
2 + (9 x 80) = 2 + 720 = 722
Answer D




Veritas Prep GMAT Instructor
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Re: In each term of a sequence, 9 is added to get the next term. If the
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20 Mar 2013, 21:10
mikemcgarry wrote: In each term of a sequence, 9 is added to get the next term. If the first term is 2, what is the eightyfirst term? (A) 632 (B) 695 (C) 713 (D) 722 (E) 731For more on sequences, as well as a complete explanation of this question, see: http://magoosh.com/gmat/2012/sequencesonthegmat/Mike Quick tip on this type of question: the GMAT is frequently counting on you (pun intended) to miscount and think the answer is off by one iteration in either direction, so the correct answer tends to not be the biggest or smallest you find. This is far from ironclad, but if you find yourself picking the biggest number (in this case E), you've probably fallen for a classic GMAT trap. The solution outlined by johnwesley above is excellent, but a lot of students find themselves doing 81*9+2 = 731 and falling into the trap. Hope this helps! Ron
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Re: In each term of a sequence, 9 is added to get the next term. If the
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22 Mar 2013, 12:23
Xo = 2 X1 = Xo + 9 = 2 + 9 X2 = X1 + 9 = (2 + 9) + 9 X3 = X2 + 9 = ((2+ 9) +9) +9
Xn = 2 + 9n X80 = 2 + 9(80)
X80 = 722 D



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Re: In each term of a sequence, 9 is added to get the next term. If the
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26 Jul 2013, 05:52
There is formula where you can find the nth term.
a + (n1)d
a = first term = 2 d = common difference = 9
so for 81th term
2 + (811)9 = 722



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Re: In each term of a sequence, 9 is added to get the next term. If the
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22 Feb 2015, 18:13
# of terms =[ (last term  first term)/interval] + 1 i.e. [(812)/1] + 1 = 80
(80*9)+2 = ANSWER



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Re: In each term of a sequence, 9 is added to get the next term. If the
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28 Feb 2015, 10:49
mikemcgarry wrote: In each term of a sequence, 9 is added to get the next term. If the first term is 2, what is the eightyfirst term?
(A) 632 (B) 695 (C) 713 (D) 722 (E) 731For more on sequences, as well as a complete explanation of this question, see: http://magoosh.com/gmat/2012/sequencesonthegmat/Mike First term = 2 common difference = 9 Nth term = First term + (N1)(common difference) So, 81th term = 2 + (811)(9) = 2 + 80*9 = 2 + 720 = 722 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: In each term of a sequence, 9 is added to get the next term. If the
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27 Feb 2017, 04:29
First term is 2 Second term is 2 + 9 = 2 +(21)9 Third term is 2 +9 +9 = 2 +(31)9 . . . . 81st term is 2 +(811)*9 = 722. Option D
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Re: In each term of a sequence, 9 is added to get the next term. If the
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01 Mar 2017, 17:21
mikemcgarry wrote: In each term of a sequence, 9 is added to get the next term. If the first term is 2, what is the eightyfirst term?
(A) 632 (B) 695 (C) 713 (D) 722 (E) 731 We are given a sequence in which 9 is added to each term and the first term is 2. Let’s list the first few terms: term 1 = 2 (notice that 2 = 9(0) + 2) term 2 = 11 (notice that 11 = 9(1) + 2) term 3 = 20 (notice that 20 = 9(2) + 2) Thus, term n = 9(n1) + 2 So the 81st term is 9(80) + 2 = 722 Alternate Solution: You might recognize this as an arithmetic sequence, with first term 2 and common difference d = 9. To determine the nth term of an arithmetic sequence, we can use the formula a_n = a_1 + (n – 1) * d. We can thus determine the 81st term as follows: a_81 = 2 + (81 – 1)(9) a_81 = 2 + (80)(9) a_81 = 722 Answer: D
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Joined: 20 Dec 2018
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Re: In each term of a sequence, 9 is added to get the next term. If the
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21 Dec 2018, 21:13
Clearly the pattern given in the question is that of an A.P. with first term = 2 and common difference = 9. So, 81st term = p = a + (n – 1)d = 2 + (81 – 1)9 = 2 + (80)9 = 722




Re: In each term of a sequence, 9 is added to get the next term. If the &nbs
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