problem - A problem that involves selecting a number of objects with given weights from a set, such that the sum of the weights is maximal but less than a pre-specified weight
A knapsack is a canvas or leather bag that you carry on your back or over your shoulder, for example when you are walking in the countryside. a bag that you carry on your shoulders = backpack, rucksack rucksack (knappsack or knapzak )