The following data applies to the basic shaft system

Tolerance for hole = 0.002 mm,

Tolerance for shaft = 0.001 mm,

Allowance = 0.003 mm,

Basic size = 50 mm,

The maximum hole size is mm(round off to 3 decimal places)

The correct answer is 50.005.

Based on the provided diagram, for a basic shaft system, the upper limit of the shaft lies on the zero line (basic size line).
Therefore, we have:
Maximum shaft size = Basic Size = 50.000 mm

The allowance represents the minimum clearance between the hole and the shaft, which is the difference between the minimum hole size and the maximum shaft size:
$\text{Allowance}=\text{Minimum hole size}-\text{Maximum shaft size}$
Substituting the given allowance of 0.003 mm, we calculate the minimum hole size:
$\text{Minimum hole size}=\text{Maximum shaft size}+\text{Allowance}$
$\text{Minimum hole size}=50.000\text{mm}+0.003\text{mm}=50.003\text{mm}$

The tolerance for the hole is 0.002 mm, which is the difference between the maximum and minimum hole sizes:
$\text{Maximum hole size}=\text{Minimum hole size}+\text{Tolerance for hole}$
$\text{Maximum hole size}=50.003\text{mm}+0.002\text{mm}=50.005\text{mm}$

Thus, the maximum hole size is 50.005 mm.