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6 votes
6 votes
Work out the sum of the first 60 terms of the following arithmetic series:
100 + 94 + 88 +...

User DANG Fan
by
2.7k points

1 Answer

14 votes
14 votes

Answer:


S_(60)=-4620

Explanation:


S_n=(n)/(2)[2a_1+(n-1)d]\\ \\S_(60)=(60)/(2)[2(100)+(60-1)(-6)] \\\\S_(60)=30[200+(59)(-6)]\\ \\S_(60)=30[200-354]\\ \\S_(60)=30[-154]\\\\S_(60)=-4620

User Raymon
by
2.9k points
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