The ordinate of a5-hr unit hydrograph of a basin is determined equal to 300 cfs at atime 4 hours after the beginning of net rainfall. What would be therunoff rate after 4 hours if a storm of uniform intensity of 3 in/hoccurs within the basin for duration of 5 hours? Use Φ index of0.5 in/h. If time time of concentration of the basinis 16 hours,what percentage area of the basin was contributing runoff at time 4hours after the beginning of rainfall?