Science:Math Exam Resources/Courses/MATH152/April 2016/Question A 09/Solution 1
Recall that the rank of a matrix is the number of leading entries (or the number of non-zero rows) in a row reduced form of the matrix.
As we see the Hint, the given augmented matrix is already in the reduced row echelon form.
By counting the number of leading entries, the rank is .
