Question:

Sum of all terms of AP $3,8,13,\ldots,373$ that are not divisible by 3 is

Step-by-Step Solution

Key Concept: $S_{75}=\frac{75}{2}(3+373)=14100$. AP of terms divisible by 3: $3,18,33,\ldots,363$, $n=25$, $S=\frac{25}{2}(3+363)=4575$.

$9525$.

Correct Answer: 9525