Answer: 201 shirts
Step-by-step explanation:
Let x= total shirts in the batch.
Total time taken for x shirts = Initial set-up time + (Time require per shirt) × (x)
[tex]\Rightarrow\ 616= 13+3x\\\\\Rightarrow\ 3x=616-13\\\\\Rightarrow\ 3x= 603\\\\\Rightarrow\ x=\dfrac{603}{3}\\\\\Rightarrow\ x=201[/tex]
Hence, there are 201 shirts in the batch.