How do Pipes in Parallel work from fluid mechanics’ point of view? What is rate of discharge in main pipe and loss of head in each pipe?

Figure below shows a system of pipes in parallel. In such a case

(a) The rate of discharge in the main pipe is equal to the sum of discharges in each of the parallel pipes, i.e.

Q =Q1 + Q2,

(b) The loss of head in each pipe is same, i.e.