Answer:
the first one is the second one
the second one is the third one
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:

50% is your answer hope i helped you
Answer: the answer should be 875 cubic feet
Step-by-step explanation:
The why is because we have to divide each rectangular prism into different pieces to use the volume formula. Doing this gives us 5*15*5 for the first part, the second part will be 20*5*5, the third square is 5*5*5.
Answer:
C. 10 000
Step-by-step explanation:
If we called:
x = children who have been vacinated against rubella only
2x = children who have been vaccinated against mumps
y = children who have been vaccinated agains both
Children who have been vaccinated against mumps only = x - y
And we know that y = 2*(x-y)
=> 2y = 3x
y = 5000
There fore x = 7500
The number of children who have been vaccinated against rubella
= 2x - y = 2*7500 - 5000 = 15 000 - 5000 = 10 000