The sum of first six terms of an AP is 42.Ratio of its 101th term to 30th term is 1:3.calculate the first and 13th term of the AP.I want to do the above question by taking six terms as a-5d,a-3d,a-d,a+d,a+3d,a+5d.How to do it by the uplisted method.I know another method but plzz tell me by this method.