MathematicsMedium178×since 2002Q5237Let SnS_nSn denote the sum of first nnn terms of an arithmetic progression. If S20=790S_{20}=790S20=790 and S10=145S_{10}=145S10=145, then S15−S5\mathrm{S}_{15}-\mathrm{S}_5S15−S5 is :A405B390C410D395Check answerSkip