The Apostles had just returned from preaching and was giving Jesus a report of what had happened. No doubt he sensed their need for rest and called them away to a place they would be alone. The multitudes however followed them. Jesus began to minister to them and it was getting late in the day and he realized their need for food. With 5000 men plus women and children it would take a lot to feed them. There would not be an adequate source for food and he called on the apostles. Pennyworth was about a days wages.