Question

If a=1 and d=3, then find S10

Answer 1

Answer:

Sn = n/2 [2a + (n-1) d]

S10 = 10/2 [2*1 + (10-1) 3 ]

S10 = 5 [2 + (9) 3 ]

S10 = 5 [2+27]

S10 = 5*29

S10 = 145

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