N(p)=4 means that there a four elements in a set P. Given: n(X u Y)=50
n(X)=20
and n(Y)=40.
Determine n(X n Y)

Jake bakes and sell apple pies. he sells each pie for $5.75 . the materials to make the pies cost $40. the boxes jake puts the pies in cost & 12.50 total. how many pies does jake need to sell to earn a profit of $50