Question

The sum of first 15 multiples of 8 is:

• A. 960
• B. 660
• C. 1200
• D. 1060

Hint:

To find the sum of first \( n \) multiples of a number, use the formula: \( a \times \frac{n(n+1)}{2} \)

Answer 1

The Correct Option is A

Sum of first \( n \) multiples of a number \( a \) is given by:
\[ S = a \times \frac{n(n+1)}{2} \]
Here, \( a = 8 \), \( n = 15 \)
\[ S = 8 \times \frac{15 \times 16}{2} = 8 \times 120 = \boxed{960} \]