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:
Answer:
the 3rd A
Step-by-step explanation:
ABACB = 5 altogether
ABACB ABA = 8
If Mary spent half of her allowance the equation will begin with 1/2x or 0.5x where x is her allowance and 0.5 is half of her allowance spent. Mary also earned 7 dollars by washing the car so this will be added to her allowance spent.
The problem says that after Mary has spent half of her allowance at the movies she was left with 18 dollars so that means that the equation must be equal to 18.
The equation you want to set up is
0.5x+7=18
Where, 18-7=11
0.5x=11
11/.5 = x
x = $22
Thus, Mary has a weekly allowance of 22 dollars.
