The tide removes sand from Sandy Point Beach at a rate modeled by the function R given by R t 2 5 sin A pumping station adds sand to the beach at a rate modeled by the function S given by S t 154 1 3t Both R and St have units of cubic yards per hour and tis measured in hours for 0 St 6 At time t 0 the beach contains 2500 cubic yards of sand Write an expression for Yt the total number of cubic yards of sand on the beach at time t