Answered

The first and last terms of a 10-term arithmetic series are listed in the table. What is the sum of the series?


Term Number Term

1 3

10 75


195

390

780

1125

Verified Answer :

meerkat18

The arithmetic sequence general formula is an = a1 + d (n-1) where d is the arithmetic difference and n is an integer. In this case, upon derivation, the formula that represents the sum of the series is S = (a1  + an)(n/2). Substituting, S = (3+75)*(10/2) equal to 390

Answer:

b. 390

Step-by-step explanation:

\(a_1 =3\\a_n=75\ =10\\\\use \ the \ arithmetic\  formula \\\\S_n=\frac{n}{2}(a_1+a_n)\\S_1_0=\frac{10}{2} (3+75)\\\\ \\S_1_0= 5 (78)\\\\S_1_0=390\\\)

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