Question

3, 8, 13, ......,373 are in arithmetic series. The sum of numbers not divisible by three is

• A. 9310
• B. 8340
• C. 9525
• D. 7325

Answer 1

Answer: (C)

9525

Answer 2

The correct option is (C): 9525
= 3 + 8 + 13 + 18 + ….. 373
$=\frac{75}{2}[3+373]=14100$
Now , $\underbrace{3 + 18 + \ldots}_{25 \text{ terms}}$
$=\frac{25}{2}[6+24.15]=4575$
$\therefore$ Required sum = 14100 - 4575 = 9525