6+12+24+..........+384= ?

A 556

B 692

C 762

D 392

Solution

Correct Answer: Option C

১ম পদ, a = 6 সাধারণ অনুপাত,
 q=12/6 =2>1 
ধরি, n তম পদ = 384 
বা, aqn-1= 384 
বা, 6(2)n-1= 384 
বা, 2n-1= 64 
বা, 2n-1=26 
বা, n-1 = 6 
..n=7 - সমষ্টি, 
s = a.(qn-1)/q-1 = 6(27-1)/2-1 =6(128 - 1) = 6 x 127 = 762

Practice More Questions on Our App!

Download our app for free and access thousands of MCQ questions with detailed solutions