In this problem DPmin corresponds to 10 cfm, DPmax corresponds to 30(1+0.5) = 45 cfm
Range of the differential pressure transducer (DPmin to DPmx) using Eq. 10.6:
Since the issue is determing the range, it is not usually needed to determine the parameters very accurately, Thus we will assume that value of C = 0.6.
To determine DP:
Note: This pressure is unreasonably high for pressure drop across an orifice. The pipe and orifice are too small for this level of flow.