On a particular day, Mary baked an equal no of lemon & cheese tarts for sale. For every lemon tart sold that day, 2 cheese tarts were sold. In the morning, she sold 3/5 of the tarts she baked. She then sold 1/4 of the remaining cheese tarts in the afternoon and had 12 cheese tarts left.
a) how many lemon tarts did she sell in the morning?
b) how many tarts did she bake altogether.