Question

Find the value of 16 + 17 + 18 + ....... + 75

• A. 2600
• B. 2850
• C. 2520
• D. 2730

Answer 1

Answer:

D. 2730

$16+17+18+........+75=S_{75}-S_{15}$

$S_{75}=n(n+1)/2=75(76)/2=2850$

$S_{15}=n(n+1)/2=15(16)/2=120$

$16+17+18+...+75=2850-120=2730$