What does μD mean when finding weight?

The table showed price paid per concert ticket on a popular online auction site. what was the average price paid per ticket

Aking and his army will attempt to capture a fortress. the left and right flanks break off from the main group to attack the west and east guard towers. suppose the left flank has a 60% chance of success and the right flank has a 75% chance of success, independently of one another. if both flanks capture their respective targets, then the king has a 98% chance of successfully taking the fort. if, however, only the left flank captures its tower, the king has an 80% chance of success; if only the right flank succeeds, the king has a 50% chance. if both flanks fail, then the king's chance of capturing the fort drops to 20%. it turns out the king captures the fort. what is the probability that one, and only one, flank was successful (either the left, or the right, but not both)? (round your answer to 3 decimal places)

The second term of an arithmetic sequence is 30. the fifth term is 90.calculatei). the commor difference of the sequence ii). the first term of the sequence tje first, second and fifth terms of the arithmetic sequence are the first three terms of a geometric sequence calculate the seventh term of the geometric sequence