Question

For an A.P. find S12 if a 4 and d=3.

Answer 1

The answer is 246

Explanation:

Given;

• n = 12
• a = 4
• d = 3

Formula;

• Sₙ = n/2 [2a + (n - 1)d]

So,

S₁₂ = 12/2 [2(4) + (12 - 1)3]

S₁₂ = 6 [8 + (11)3]

S₁₂ = 6 × (8 + 33)

S₁₂ = 6 × 41

S₁₂ = 246

Thus, The S₁₂ of given A.P is 246