arithmetic
posted by Anonymous on .
given that the first term of an Ap is 7 and its 10th term is twice the second term. calculate the sum of the 28 term.

given that the first term of an Ap is 7 and its 10th term is twice the second term.calculate the 19th term, the sum of the 28 term and the common different between the 9th and the 6th term..