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If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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02 Jun 2016, 10:52
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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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02 Jun 2016, 12:49
Stm1 : a = first term = 23. We don't know anything about the kind of the series. So not sufficient, Stm2 : Now we know that we are dealing with an arithmetic progression. nth term of an AP = a + (n1)d. We know n = 83, and we know d = 5, But we don't know a, the first term of the series. Not sufficient.
Combining, we know all we need to calculate the 83rd term. Hence C.



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If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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02 Jun 2016, 23:23
st1: a=23, n=100, we dont have information about d=? so it is not sufficient. st2: n=100, d=5, we dont have information about a=? so it is also not sufficient. st1 & st2: a=23, n=100, d=5. we can find 83 rd term by using the formula. t83= a+(831)d. so c is the answer.
Last edited by Harish Yannam on 02 Jun 2016, 23:49, edited 1 time in total.



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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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02 Jun 2016, 23:37
Bunuel wrote: If sequence S has 100 terms, what is the 83rd term of S?
(1) The first term of S is 23 (2) Each term after the first term of S is 5 less than the preceding term Statement 1We only know the first term and total terms. But we do not know the Common difference as well as the type of progression. (AP or GP) Not sufficient.Statement 2This statement tells us that common difference is (5). However we do not know the first term. So we cannot find the 83rd term with this information. Not sufficient.Combining Statements 1 and 2We know a = 23. We know d = 5 Nth term = a+(n1)d So sufficient. (C) is the answer.



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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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03 Jun 2016, 10:32
Bunuel wrote: If sequence S has 100 terms, what is the 83rd term of S?
(1) The first term of S is 23 (2) Each term after the first term of S is 5 less than the preceding term (1) The first term of S is 23 No idea if the sequence is consecutive numbers or random numbers or any other pattern. Not sufficient (2) Each term after the first term of S is 5 less than the preceding term. We are not given any term. Not sufficient. Combining both statements: If first term is 23 and each following term is 5 less than the previous term, then we could find out 83rd term. Sufficient C is the answer
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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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05 Jun 2016, 04:02
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Bunuel wrote: If sequence S has 100 terms, what is the 83rd term of S?
(1) The first term of S is 23 (2) Each term after the first term of S is 5 less than the preceding term The question didn't mention any progression between the number of element.Only progression/relationship between numbers can guarantee a specific sequence. For example, In an arithmetic progression, 83 th term=A + D(831) ,A=First number of the sequence,D=common difference between two numbers. Statement 1: Knowing only first term(A=23) is not sufficient to know the 83th term.Still we need more information. Not SufficientStatement 2: knowing only the common difference between two numbers (D=5)in not sufficient to know any specific progression. Not SufficientCombining two statements together we can find the 83 th term =23+5(831)=23+410=433, SufficientSo, Correct Answer C
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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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15 Jun 2016, 14:25
Bunuel wrote: If sequence S has 100 terms, what is the 83rd term of S?
(1) The first term of S is 23 (2) Each term after the first term of S is 5 less than the preceding term Target question: What is the 83rd term of S? Statement 1: The first term of S is 23 We have no idea how this sequence progresses. So, there's no way to determine the 83rd term. Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: Each term after the first term of S is 5 less than the preceding termOkay, so we know HOW the sequence progresses, but we don't know the specific value of any term. Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT Statements 1 and 2 combined Term 1 = 23 (from statement 1) Term 2 = 23  5 = 18 (from statement 2) Term 3 = 18  5 = 13 And so on.... Since we COULD keep this pattern going indefinitely, we COULD easily find the value of the 83rd term. Of course, we're not going to waste any time determining the actual value of the 83rd term. All we need to do is determine whether the combined statements are sufficient to answer the target question. Since we COULD answer the target question with certainty, the combined statements are SUFFICIENT Answer = Cheers, Brent
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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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23 Sep 2016, 20:32
Is it true that C is the correct answer because to determine a specific value in the list, we need (1) a starting/reference point and (2) a formula that is applied to generate all of the elements of the set?



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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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23 Feb 2017, 04:48
Prompt analysis An arithmetic progression following the sequence as tn = a +(n1)d has 100 terms.
Superset The answer will be any real number.
Translation In order to find t83, we need a and d or any two equation to solve for a and d.
Statement analysis
St 1: a = 23. We don't have any idea about d. INSUFFICIENT. Hence a and d eliminated. St 2: d = 5. We don't have any idea about a. INSUFFICIENT. Hence a, b and d eliminated. St 1 & St 2: we know a =23, n=83 and d =5. We can find the value of t83 with the above mentioned formula
Option C



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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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20 Aug 2017, 10:54
Hi, I have a doubt in this question. Some people are saying common difference is 5 and and some are saying saying common difference is 5 I know Sn = a1+(n1)d but, shuld I take d as +ve or ve? If we take from question it is clear that d is ve..
Can some one help me .
Thanks,



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Re: If sequence S has 100 terms, what is the 83rd term of S? [#permalink]
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03 Oct 2017, 07:27
Hi Brent,
Could you please explain  how could we find value of 83rd term by recognizing the pattern for this?




Re: If sequence S has 100 terms, what is the 83rd term of S?
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03 Oct 2017, 07:27






