Answer & Explanation
B) 29.39 cm
Volume of water flowing through 1 pipe of diameter x = Volume discharged by 6 pipes of dia 12 cms
As speed is same, area of cross sections should be same.
Area of bigger pipe of diameter x = Total area of 6 smaller pipes of diameter 12
Here R = R and R1 = 12/2 = 6
R = 14.696
=> D = X = 14.696 x 2 = 29.3938 cm.