It means that $6 is a fixed charge for pattern making on an order of shirts while the cost for the number of T-shirts produced is equivalent to the product of 11 and the number of shirts in dollars.
This explains the function $11n + $6 where n is the number of T-shirts produced with the same pattern.
As such, the cost for 5 T-shirts will be
=11(5) + 6
=55 + 6
= $61
The total cost for 5 T-shirts with the same pattern is $61.
