Q. 15 D5.0( 1 Vote )

# If a = 2 and d = 4, then S20 = _____A. 600B. 800C. 78D. 80

We have a = 2

d= 4

n = 20

we also know that, Sn = × (2a + (n – 1)d)

S20 = × (2(2) + (20 – 1)4)

S20 = 10 × (4 + 19 × 4)

S20 = 10 × (4 + 76)

S20 = 10 × 80

S20 = 800

the correct option is (b)

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