If \( {}^{1}P_{1}+2\cdot {}^{2}P_{2}+3\cdot {}^{3}P_{3}+\ldots+15\cdot {}^{15}P_{15}={}^qP_{r-s},\; 0\le s\le 1 \), then \( {}^{\,q+s}C_{\,r-s} \) is equal to ________.