Steps for

Problema $9\mathrm{.}3($Chin$,$ edited$)$ A rainfall $($mm$)$ record contains $50$ years

of measurements at $5-$min intervals. The maximum rainfall amounts for

$5-$min intervals of $5$min,$10$min,$15$min,$20$min,$25$min and $30$ min are

ranked as follows:

Do not use excell. Explain each step and equation