There are two sets `M_1` and `M_2` each of which consists of three numbers in arithmetic sequence whose sum is 15. Let `d_1` and `d_2` be the common differences such that `d_1=1+d_2` and `8p_1=7p_2` where `p_1` and `p_2` are the product of the numbers respectively in `M_1` and `M_2`. If `d_2 gt 0` then find the value of `(p_2-p_1)/(d_1+d_2)`