wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The sum of first 20 terms of the sequence 0.7,0.77,0.777,..., is

A
781[1791020]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
79[991020]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
781[179+1020]
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
79[99+1020]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 781[179+1020]
S=0.7+0.77+0.777+...upto 20 terms
S=79[0.9+0.99+0.999+...upto 20 terms
9S7=(10.1)+(10.01)+(10.001)+...
9S7=20[110+1100+11000+...upto 20 terms]
=20110⎜ ⎜ ⎜ ⎜ ⎜1(110)201110⎟ ⎟ ⎟ ⎟ ⎟
9S7=20110209
S=781[179+1020]

flag
Suggest Corrections
thumbs-up
4
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Geometric Progression
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon