Question

Find the sum of the first 10 terms of the arithmetic sequence if a1= 3 and d=0.2​

Answer 1

Answer:

answer is 12

Step-by-step explanation:

Sum of first 10 terms=10/2{2a+(10-1)d}

S10=5{6+1.8}

S10=5×2.4

S10 = 12

Answer 2

Answer: 39

Step-by-step explanation:

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

S10 = 10/2 [2(3) +(10-1) 0.2]

      = 5 [6 + 9] 0.2]

      = 5 [6+1.8]

      = 5 [7.8]

S10 = 39