IMSO 2010 Mathematics - International Essay Question 2

Let $P=1\times2\times3\times4\times5\times6\times7\times8\times9\times10\times11\times12\times13\times14\times15$ and $Q=1+2+3+4+5+6+7+8+9+10+11+12+13+14+15$. What is the remainder when $P$ is divided by $Q$?