Below are the 2016 Grade 9 Math Challenge – Elimination Round questions and answers – Part I. More reviewers can be found on the Past Tests and All Posts pages.
1.) Solve for x in 
2.) Find 
3.) What is the value of
4.) Solve for x in
5.) Solve for x in 
6.) Find the sum of the first 20 positive odd numbers.
7.) Solve for x in
8.) Find all possible values of x if one of the interior angles of a square is
9.) What is the sum of the interior angles of a pentagon?
10.) The supplement of an angle is four times its complement. Find the angle.
11.) What is the shortest side of 
12.) Rationalize the denominator and simplify:
13.) Find the 25th term of the arithmetic sequence whose first 3 terms are 4, 7, and 10.
14.) Solve for x in
15.) For what value/s of x is
16.) In 
17.) The angle bisector at vertex B of 
18.) Find the equation of the line parallel to 
19.) Express in terms of sines or cosines of 
20.) Find the common ratio of a geometric sequence whose first term is -2 and the 7th term is -1458.
21.) Solve for x in
22.) Find the 7th term of the geometric sequence 8, 12, 18, …
23.) Triangle ABC is a righttriangle with 
24.) Two of the exterior angles of a regular polygon measure 
25.) Solve for x in:
Answer key:
1.) -14
2.)
3.)
4.) 0 or 3
5.)
6.) 400
7.) 3 < x < 4
8.) -5, 9
9.)
10.)
11.) PQ
12.)
13.) 76
14.) 0 or 4
15.) all real numbers or
16.)
17.) 10
18.) 4x + 3y = -36
19.)
20.)
21.)
22.)
23.)
24.) 15
25.) 2
View Part II here: 2016 Grade 9 Math Challenge – Elimination Round with answer key – Part II
