Boyle's law states that if the temperature of a gas remains constant, then $PV=c,$ where, $P=$ pressure, $V=$ volume and $c$ is constant. Given a quantity of gas at constant temperature, if $V$ is decreasing at a rate of $15\frac{in3}{se{c}^3},$ at what rate is $P$ increasing when $P=70\frac{lb}{i{n}^2}$ and $V=50in3?($Do not round.$)$

Water is falling on a surface, wetting a circular area that is expanding at a rate of $10\frac{mm}{sec}.$

How fast is the radius of the wetted area expanding when the radius is $144mm?$