What does this symbol "ll” mean?

In the diagram of AABC, points D and E are on AB and CB,
respectively, such that AC | DE.

What does "AC||DE" tell us? Why do we need this
information?

If AD = 24, DB = 12, and DE = 4, what is the length of AC ?
(1) 8
(3) 16
(2) 12
(4) 72
Show your calculation below to find the answer.

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a.about 4 b.about 8 c.about 40 d.about 21

What is the absolute value of the complex number -4-sqrt2i

Consider a bag that contains 220 coins of which 6 are rare indian pennies. for the given pair of events a and b, complete parts (a) and (b) below. a: when one of the 220 coins is randomly selected, it is one of the 6 indian pennies. b: when another one of the 220 coins is randomly selected (with replacement), it is also one of the 6 indian pennies. a. determine whether events a and b are independent or dependent. b. find p(a and b), the probability that events a and b both occur.