A delivery drone flies at a constant speed. The distance $d_1$, in meters, it travels from its base after $t$ seconds is given by $d_1=8t$. A second, older drone flies at a constant speed, and the distance $d_2$, in meters, it travels from its base after $t$ seconds is given by $d_2=5t$. How many more meters will the first drone have traveled than the second drone after 15 seconds?