b$)$ Rainfall over a basin in three consecutive hours are $4cm,5cm$ and $3$ cm respectively. Estimates

surface runoff from the basin assuming negligible surface retention and evaporation losses. The

infiltration loss can be estimated using the following Horton's equation

$f_p=1\mathrm{.}2+4\mathrm{.}2e^{-2\mathrm{.}5t}$

Where, $f_p$ is in $c\frac{m}{h}$ and t is in hours.