The sum of the first n terms in the sequence 8, 88, 888, 8888, … is _____.

GATE · 2020 · ME · Set 1 · General Aptitude

1. A.

   $\frac{81}{80}(10^n-1)+\frac{9}{8}n$

2. B.

   $\frac{81}{80}(10^n-1)-\frac{9}{8}n$

3. C.

   $\frac{80}{81}(10^n-1)+\frac{8}{9}n$

4. D.

   $\frac{80}{81}(10^n-1)-\frac{8}{9}n$