5 and 15 are the first two term

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5 and 15 are the first two term

by BTGmoderatorDC » Fri Nov 24, 2017 5:39 am
5 and 15 are the first two terms in a geometric sequence. What is the arithmetic difference between the 11th term and the 13th term?

A. 3*5^2
B. 5* 3^13 - 5 * 3^11
C. 5^13
D. 40 * 3^10
E. 3^12 - 3^10

Can some experts help me find the best solution in this problem?

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5 and 15 are the first two term

by Brent@GMATPrepNow » Fri Nov 24, 2017 8:56 am
lheiannie07 wrote:5 and 15 are the first two terms in a geometric sequence. What is the arithmetic difference between the 11th term and the 13th term?

A. 3*5^2
B. 5* 3^13 - 5 * 3^11
C. 5^13
D. 40 * 3^10
E. 3^12 - 3^10

Can some experts help me find the best solution in this problem?

OA D
hi lheiannie07,

You posted this same question last month: https://www.beatthegmat.com/5-and-15-are ... 97485.html

By the way, the GMAT does NOT expect students to know the terms "geometric sequence" and "arithmetic difference."
IF the test-makers were to use these terms in a question, they'd provide definitions as well.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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by BTGmoderatorDC » Wed Jan 17, 2018 9:33 pm
Brent@GMATPrepNow wrote:
lheiannie07 wrote:5 and 15 are the first two terms in a geometric sequence. What is the arithmetic difference between the 11th term and the 13th term?

A. 3*5^2
B. 5* 3^13 - 5 * 3^11
C. 5^13
D. 40 * 3^10
E. 3^12 - 3^10

Can some experts help me find the best solution in this problem?

OA D
hi lheiannie07,

You posted this same question last month: https://www.beatthegmat.com/5-and-15-are ... 97485.html

By the way, the GMAT does NOT expect students to know the terms "geometric sequence" and "arithmetic difference."
IF the test-makers were to use these terms in a question, they'd provide definitions as well.

Cheers,
Brent
Thanks a lot!