## College Algebra (10th Edition)

$2.285$ miles an hour.
Let $x$ be the current velocity, then the upstream velocity is $16-x$, the downstream velocity is $16+x$. Then our equation is: $(16-x)\cdot20=(16+x)\cdot15\\320-20x=240+15x\\80=35x\\x\approx2.285$ Thus the current speed is $2.285$ miles an hour.