Two for two. I decided to try a different kind of thinking. “Got a puzzle for you. You need to measure out exactly four liters of water, but all you’ve got is two jars and a water hose. One jar holds exactly three liters, the other exactly five. There are no markings on the jars. How do you do it?” She didn’t even hesitate. “Fill the five jar. Dump what you can into the three, leaving two liters. Empty the three jar, then pour the remaining two into it, leaving space for one. Refill the empty five, and pour what you can into the three. Exactly four liters will be left.”
