There are 1000 lockers in a high school with 1000 students. The problem begins with the first student opening all 1000 lockers; next the second student closes lockers 2,4,6,8,10 and so on to locker 1000; the third student changes the state (opens lockers that are...
This month’s brain teaser is on the “easier” side (though it is still a brain teaser: hint, hint). As in previous newsletters, it’s also typical of the type of questions you see on standardized tests, especially the GMAT and GRE: If 4 hens can lay 4 eggs in...
Club X has more than 10 but fewer than 40 members. Sometimes the members sit at tables with 3 members at one table and 4 members at each of the other tables, and sometimes they sit at tables with 3 members at one table and 5 members at each of the other tables. If...
A census taker approaches a house and asks the woman who answers the door “How many children do you have, and what are their ages?” The woman says, “I have three children; the product of their ages is 36, and the sum of their ages is equal to the...
This month we switch back to a more quantitative brain teaser. It’s also typical of the type of question one sees on the GMAT and GRE, for reasons that we explain in the answer explanation. Are you up for the challenge? When a clock is at 3:15, what is the separation...
