i don't know how to type the answer out but it's on the work i just did ⬆️
The key word here is "or". If it's an OR question, you add the probabilities together. If it says "and", you multiply them together
As it is an OR question though, you add them.
So:
15 + 5 = 20%
Answer:
Step-by-step explanation:

Answer:
C. True; by the Invertible Matrix Theorem if the equation Ax=0 has only the trivial solution, then the matrix is invertible. Thus, A must also be row equivalent to the n x n identity matrix.
Step-by-step explanation:
The Invertible matrix Theorem is a Theorem which gives a list of equivalent conditions for an n X n matrix to have an inverse. For the sake of this question, we would look at only the conditions needed to answer the question.
- There is an n×n matrix C such that CA=
. - There is an n×n matrix D such that AD=
. - The equation Ax=0 has only the trivial solution x=0.
- A is row-equivalent to the n×n identity matrix
. - For each column vector b in
, the equation Ax=b has a unique solution. - The columns of A span
.
Therefore the statement:
If there is an n X n matrix D such that AD=I, then there is also an n X n matrix C such that CA = I is true by the conditions for invertibility of matrix:
- The equation Ax=0 has only the trivial solution x=0.
- A is row-equivalent to the n×n identity matrix
.
The correct option is C.