What is the sum of the digits of the first 99 counting numbers?

Which of the following system of equation is not equal to the system of equations is not equal to the system of equations shown below

Brian, chris, and damien took a math test that had 20 questions. the number of questions brian got right is 14 more than the number of questions chris got right. damien correctly answered 2 less than the number of questions chris answered correctly. if brian and damien have the same score, which statement is true?

If eh = hg and hg=16, find the diameter of k