Suppose you have a list of numbers from zero to one hundred. How quickly can you add them all up without using a calculator? Show Hint ▼ HINT: There is a swift way to add these numbers. Think about how the numbers at the opposite ends of the list relate to each other. Show Answer [...]
“GIVE ME CHANGE for a dollar, please.” said the customer. “I’m sorry.” said Miss Jones, the cashier, after searching through the cash register, “but I can’t do it with the coins I have here.” “Can you change a half dollar then?” Miss Jones shook her head. In fact, she said, she couldn’t even make change [...]
IF THREE CATS catch three rats in three minutes, how many cats will catch 100 rats in 100 minutes? Show Answer ▼ The usual answer to this old riddle is as follows. If it takes three cats three minutes to catch three rats, it must take them one minute to catch one rat. And if [...]
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