?
How many terms are there in the GP 5, 20, 80, 320........... 20480?
Answer & Solution
Correct Answer:
Option
E
Common ratio, r = $$\frac{{20}}{5}$$ = 4
Last term or nth term of GP = arn - 1
20480 = 5 × (4n - 1)
Or, 4n - 1 = $$\frac{{20480}}{5}$$ = 46
So, comparing the power,
Thus, n - 1 = 6
Or, n = 7
Number of terms = 7
Join the Discussion
Login to post a comment or share your explanation.
LoginBcoz 20480/5=4096=4 to the power 6 not 8
n-1=6
n=7
4^6=4^(n-1)
n-1=6
N=7