Find S10 if a = 6 and d = 3

Find S10  if a = 6 and d = 3

Answer:

For an A.P.

Sn = n [ 2a + (n – 1) d ] 2 ∴ S10   = 10 [ 2(6) + (10 – 1)3 ] 2 ∴ S10 = 5 [ 12 + 27  ] ∴ S10 = 5 [39] ∴ S10 = 195