An apartment building has eight floors. if seven people get on the elevator on the first floor, what is the probability they all want to get off on different floors

We have been given that there are total 8 floors and 7 people get on the elevator on the first floor.

Therefore, the total number of possible outcomes are

Now, on the second floor any person can get off. So there are total 7 possibilities for second floor.

Now, since 1 person is already get off in the second floor, so on the third floor there are 7  possibilities.

Similarly, for

fourth - 5 possibilities

fifth -     4  possibilities

sixth-     3  possibilities

seventh -     2  possibilities

eight -     1  possibility

Therefore, the required probability is given by

Therefore, the probability is 0.00612

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

use this formula:

p(a\b) = p(a and b)/p(b).

take it from here.