Problem of The Week: Due Friday, September 3

Senta and Maurice are lab partners in science class.  Today they have to weigh liquid.  They have a tray of 80 weights which they can use.  The weights are of 4 different kinds:  50g, 25g, 15g, and 5g.  The first liquid weighs 85g.  How many different combinations of weights will balance the scale for the first liquid?