From the information available, pear trees are planted and as more of them are planted then more barrels of pears will be produced.
This means the number of barrels will DEPEND on the number of trees planted, whereas the number of trees planted can be any amount and does not depend on the number of barrels.
ANSWER:
P is independednt and B is dependent
Where
p = number of pear trees that have been planted in the orchard
b = the number of barrels of pears the orchad will produce