Consider three blood vessel segments of equivalent length and diameter: vessels a, b, and c. pressure at the beginning of each segment is as follows:
a) p = 100 mmhg;
b) p = 80 mmhg;
c) p = 60 mmhg.
pressure at the end of each segment is as follows:
a) p = 70 mmhg;
b) p = 50 mmhg;
c) p = 30 mmhg. which vessel has the greatest blood flow through the described segment?

A, B and C. All have same blood flow.

Explanation:

The hemodynamic relation between blood flow (F), resistance (R)  and pressure difference (ΔP) can be expressed as

F = ΔP/R

RESISTANCE:

Since the three blood vessel segments are of equal length and diameter, it implies that all three blood vessel segments possess equal resistance.

Since the resistance is same in all vessels therefore, in this case blood flow depends on pressure differences.

PRESSURE DIFFERENCES:

ΔP in vessel segment (A):

100-70= 30 mmHg

ΔP in vessel segment (B):

80-50= 30 mmHg

ΔP in vessel segment (C):

60 -30 = 30 mmHg

CONCLUSION:

Since the pressure differences is same i.e. 30 mmHg in all vessel segments and resistance is also same, therefore blood flow will be same in all vessel segments.