This video explains how to solve the problem of probability dependent events. In this video the problem is that a box contains three pens, 2 markers, and 1 highlighter. The person selects one item at random and does not return it to the box. So what is the probability that the person selects 1 pen and 1 marker. That is 6 items total. First she count the all items that involved in this problem. Then count the individual probability of the pen and marker. The person selects 3 pens out of 6 items so the probability is 3/6. Out of three pens she fix with a pen so the number of pens goes down to 2. She did not pick a marker so it is 2 out of 2. She does not take the highlighter too. So total is 5. Next take the markers probability is out of 2 markers in the 5 items is 2/5. Next calculate combined probability by combined the pen and marker probability. That is 3/6 x 2/5. So it is equal to 6/30. That is the way described in this video that how to calculate the probability dependent events.