Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?
Can you replace the question mark with the correct number in the below table sequence?
I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?
