6)What is the sum of the first six terms of an AP whose first term is 3 and the sixth term is 27?
60
70
80
90
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Answer:
S₆=90
Step-by-step explanation:
Given: a=3; a₆=27
To Find: S₆=?
Solution:
S₆= n/2 (a + a₆)
S₆ =6/2 (3 + 27)
S₆ = 3(30)
S₆=90
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