There are three shifts at an automobile plant. Shift 1 makes 50%, shift 2 makes 40%, and shift 3 makes 10% of the vans produced in the plant. It is known that shift 1 has a defective rate of 1%, shift 2’s defective rate is 2%, and shift 3’s defective rate is 6%. A customer recently purchased a van made at the plant and complains that it is defective. Calculate the probability that the van was made in shift 2.