It is already given in the question that there are 8 pencils in 1 packet. Based on this information the answer to the question can be easily found out.
Then
Number of pencils in 7 packets = 8 * 7
= 56
So there are 56 pencils in 7 packets. I hope you have got the answer you were looking for. This method would allow you to answer any question of this type.
