- Home
- Standard 11
- Mathematics
8. Sequences and Series
normal
What is the sum of all two digit numbers which give a remainder of $4$ when divided by $6$ ?
A
$777$
B
$776$
C
$780$
D
$784$
Solution
Such numbers are $10,16, \ldots . .94$
If $\mathrm{n}$ be the number of terms, then
$94=t_{n}=a+(n-1) d=10+(n-1) 6 \Rightarrow n=15$
$\therefore {\mathop{\rm sum}\nolimits} = \frac{{\rm{n}}}{2}({\rm{a}} + l) = \frac{{15}}{2}(10 + 94) = 780$
Standard 11
Mathematics