GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
A certain sequence is defined by the formula an = an – 1 – 7
[#permalink]
30 Jul 2018, 10:28
30 Jul 2018, 10:28
1
Expert Reply
00:00
Question Stats:
48% (01:19) correct
51% (01:26) wrong based on 95 sessions
Hide Show timer Statistics
A certain sequence is defined by the formula \(a_n = a_{n – 1} – 7\).
\(a_7 = 7\)
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
\(a_7 = 7\)
Quantity A |
Quantity B |
\(a_1\) |
\(-35\) |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
Re: A certain sequence is defined by the formula an = an – 1 – 7
[#permalink]
12 Aug 2018, 05:41
12 Aug 2018, 05:41
1
Expert Reply
Explanation
The sequence \(a_n = a_{n - 1} - 7\) can be read as “to get any term in sequence a, subtract 7 from the previous term.” The problem provides the 7th term; plug the term into the function in order to determine the pattern.
Note that Quantity A asks for the value of a1, so try to find the 6th term:
\(7 = a_6 - 7\)
\(a_6 = 14\)
In other words, each previous term will be 7 greater than the subsequent term. Therefore, \(a_7 = 7\), \(a_6 = 14\), \(a_5 = 21\), and so on.
The term \(a_1\), then, is greater than the starting point, 7, and must also be greater than the negative value in Quantity B. Quantity A is greater. Note that the value in Quantity B is the result of incorrectly subtracting 7 six times, rather than adding it.
The sequence \(a_n = a_{n - 1} - 7\) can be read as “to get any term in sequence a, subtract 7 from the previous term.” The problem provides the 7th term; plug the term into the function in order to determine the pattern.
Note that Quantity A asks for the value of a1, so try to find the 6th term:
\(7 = a_6 - 7\)
\(a_6 = 14\)
In other words, each previous term will be 7 greater than the subsequent term. Therefore, \(a_7 = 7\), \(a_6 = 14\), \(a_5 = 21\), and so on.
The term \(a_1\), then, is greater than the starting point, 7, and must also be greater than the negative value in Quantity B. Quantity A is greater. Note that the value in Quantity B is the result of incorrectly subtracting 7 six times, rather than adding it.
Re: A certain sequence is defined by the formula an = an – 1 – 7
[#permalink]
25 Oct 2018, 04:37
25 Oct 2018, 04:37
I didnt get it
