In the given figure lines BC||PQ if ABP=105? find DCQ?

First of all, we will find PBC by linear pair : ABP+PBC= 180  =  105+PBC=180  =  PBC=180-105=75. 
Therefore, we can say anglePBC=angleDCQ=75degree  (co interior angles on the same side of the transversal)....hope this works!!!