Question 927792: There are two geometric sequences with 3nd term 5 and 5th term 80. What are the two possible values of the 4rd term?
Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! There are two geometric sequences with 3nd term 5 and 5th term 80. What are the two possible values of the 4rd term?
a(3) = ar^2 = 5
a(5) = ar^4 = 80
===
Divide and solve for "r"::
r^2 = 16
r = +4 or r = -4
------
If r = +4, a = 5/16 and a(4) = (5/16)r^3 = (5/16)*4^3 = 20
If r = -4, a = 80/64 = 5/4 and a(4) = (5/4)(-4)^3 = 5(-16) = -80
--------------------------
Cheers,
Stan H.
------------
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website!
There are two geometric sequences with 3nd term 5 and 5th term 80. What are the two possible values of the 4rd term?
Term 4, or  could be 
You can do the check!!
===================
If you need a complete and detailed solution, let me know!!
Send comments, “thank-yous,” and inquiries to “D” at MathMadEzy@aol.com.
Further help is available, online or in-person, for a fee, obviously.
For FREE info and answers to questions about the ASVAB exam, the NYS 3 – 8 city/state wide exams,GENERAL
MATH and HOMEWORK QUESTIONS, or MATH QUESTIONS related to the Regents Integrated Algebra,
Regents Geometry, Regents Algebra 2/Trigonometry, SHSAT, COOP/HSPT/TACHS, PSAT, SAT, ACT, SSAT/ISEE,
GRE, CLEP, and the TASC/GED, you can visit: http://asvabstudyzone.freeforums.net/.
|
|
|
