Question

The sum of integer from 1 to 100 that are divisible by 2 or 5 is

• A. 3000
• B. 3050
• C. 4050
• D. None of these

Answer 1

Answer: (B)

3050

Answer 2

(2 + 4 +……+ 100) + [5 +.10 + 15 +….. + 100]

[10 + 20 + ….. + 100]

= $\frac { 50 } { 2 }$×(2 + 100) + $\frac { 20 } { 2 }$ (5 + 100) –$\frac { 10 } { 2 }$(10 + 100)

= 25 × 102 + 1050 – 550 = 2550 + 1050 – 550

= 3600 – 550 = \begin{tabular} { | l | } \hline 3050 \ \hline \end{tabular}