Question

Find the sum of the AP -37, -33, -29,….12 terms.

Answer 1

Sum of n terms of AP formula:

Where

First term = a

Common difference = d

Number of terms = n

-37, -33, -29,….12 terms.

a = -37

d = (-33) – (-37) = 4

Using (1)

S₁₂ = 12/2 [2(-37) + (12 – 1)(4)]

= (6)(-74 + 44)

= 6 × (-30)

= – 180

Sum of 12 terms of this AP is – 180.