A bakery is creating a round cake with three different levels as shown below. The diameters of the three cakes are 10 in, 8 in, and 6 in. The cakes are stacked and centered on top of each other with the largest cake on the bottom and the smallest cake on top. In order to plan the decorations for the cake, the bakery needs to determine the total exposed area available for decoration on the top faces of the three cakes (the sides of each cake will not be decorated). What is the total exposed area, in square inches, of the top faces of the three cakes?

A
25π in2

B
50π in2

C
100π in2

D
200π in2

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.