Question

in an arithmetic progression the 13th term is 27 and the 7th term is three times the second term find;the common difference,the first term and the sum of the first ten terms

Answer 1

a+12d = 27
a+6d = 3(a+d)

Now you can find a and d, and then get

S10 = 10/2 (2a+9d)

Answer 2

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