The drainage area of a watershed is 50 km2. The ϕ - index is 0.5 cm/hour and the base flow at the outlet is 10 m3/s. One hour unit hydrograph (unit depth = 1 cm) of the watershed is triangular in shape with a time base of 15 hours. The peak ordinate occurs at 5 hours.
For a storm of depth of 5.5 cm and duration of 1 hour, the peak ordinate (in m3/s ) of the hydrograph is