Answer:
11.42 boxes
Step-by-step explanation:
For the first box bought, there is a 100% chance of getting a unique toy (since you still don't have any). E₁ = 1.
After that, there is a 4 in 5 chance of getting a unique toy from the next box, the expected number of boxes required is:

For the next unique toy, there is now a 3 in 5 chance of getting it:

Following that logic, there is a 2 in 5 chance of getting the 4th unique toy:

Finally, there is a 1 in 5 chance to get the last unique toy:

The expected number of boxes to obtain a full set is:

No, the 2 lines can never ever be both parallel and perpendicular if I'm not mistaken. This is because a set of parallel lines will never touch each other at all. However perpendicular lines are two lines that meet up to get an angle of 90. You cannot have two lines that never touch and touch at the same time.
Answer:
Step-by-step explanation:
i wont tell you the answer but if you use brainly all the time you will not learn how to do it so try hard get a pen or a pencil get paper and stay confident you got this! i belive in you
Answer:
Not Parallel
Step-by-step explanation:
I think so sorry If I'm wrong