Three pipes steadily deliver water at 20°C to a large exit pipe in Fig. P3.8. The velocity V2=5 m/s, and the exit flow rate Q4=120 m3/h. Find (a)V1, (b)V3, and (c)V4 if it is known that increasing Q3 by 20 percent would increase Q4 by 10 percent. The pipe diameters are D1=4 cm, D2=5 cm, D3=6 cm, D4=9 cm.