Question

The value of the sum $8 + 16 + 24 + 32 + \cdots + 80$ is

• A. 420
• B. 440
• C. 400
• D. 450

Hint:

For evenly spaced multiples, divide last term by step to get number of terms.

Answer 1

The Correct Option is B

Concept: This is an arithmetic progression (A.P.) sum. Formula: \[ S_n = \frac{n}{2}(a + l) \] Explanation: First term $a = 8$ Last term $l = 80$ Common difference = 8 Number of terms: \[ n = \frac{80}{8} = 10 \] Sum: \[ S = \frac{10}{2}(8 + 80) = 5 \times 88 = 440 \]