What is wrong with the following proof?
2=1
a = b
a2 = ab
a2 – b2 = ab – b2
(a+b)(a-b) = b(a-b)
a + b = b
2b = b
2 = 1
Hard Riddles
Three Friends
At school Joe has three friends: Tim, George and Paige. Two of them play football, two play tennis, and two play golf. The friend who doesn’t play golf doesn’t play tennis and the one who doesn’t play football doesn’t play golf. Paige doesn’t play tennis. Which sports does each person play?
Riddle AnswerQuarter on the Table
Your friend pulls out a perfectly circular table and a sack of quarters, and proposes a game.
“We’ll take turns putting a quarter on the table,” he says. “Each quarter must lay flat on the table, and cannot sit on top of any other quarters. The last person to successfully put a quarter on the table wins.”
He gives you the choice to go first or second. What should you do, and what should your strategy be to win?
Riddle Answer4 Trees Same Distance
A smart landscaper is given the task of placing 4 trees so that they are all the same distance away from each other. How does he do this?
Riddle AnswerSpy, Liar and Truthteller
Alice, Bob and Charlie are one of each type:
- a truth teller (always tells the truth)
- a liar (always lies)
- and a spy (can lie or tell the truth)
They make the following statements:
Alice: I am not a truth teller.
Bob: I am not a spy.
Charlie: I am not a liar.
What type is Charlie?
- Truth teller
- Liar
- Spy
- There is not enough information