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Mathematics

If the nth term of an A.P. is 3n + 2, then the sum of its first three terms is :
9n - 6
30
48
24

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Given,

a_n = 3n + 2

a₁ = 3(1) + 2 = 3 + 2 = 5,

a₂ = 3(2) + 2 = 6 + 2 = 8,

a₃ = 3(3) + 2 = 9 + 2 = 11.

By formula,

Sum of A.P. = $\dfrac{n}{2}(a + l)$

Sum of first three terms = $\dfrac{3}{2}(5 + 11) = \dfrac{3}{2} \times 16$

= 3 × 8 = 24.

Hence, Option 4 is the correct option.

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