St. Cloud State University offers these brainbusters to illustrate the difficulty of the tests that math contest participants will face Thursday. Check back at 3 p.m. CDT for the answers.
7th-8th grade: A store marks all its items up by 30 percent, but all items are 10 percent off on Mondays. What would be the actual percent increase of the price of the items on Monday?
a) 12 percent, b) 17 percent, c) 20 percent, d) 27 percent, e) 40 percent
9th-10th grade: I have a friend who always lies on Mondays, Wednesdays, Thursdays, but always tells the truth on the other days of the week. One morning he said, "This is NOT one of my lying days." Later in the day he said, "The day after tomorrow IS one of my lying days." What day of the week was it when he said this?
a) either Monday or Saturday b) either Monday or Wednesday c) either Tuesday or Friday d) either Wednesday or Friday e.) either Wednesday or Saturday
11th-12th grade: The lines L and K are symmetric to each other with respect to the line y = -x. If the equation of the line L is y = ax+b with a and b not zero, then the equation of K is y =?
a) -x/a + b/a b) -x/a - b c) -x/a + b/a d) x/a + b/a e) x/a - b/a
