50% of the apartments in a certain building have windows and hardwood floors. 25% of the apartments without windows have hardwood floors. If 40% of the apartments do not have hardwood floors, what M percent of the apartments with windows have hardwood floors? Choose one:
A) 10  B) 16 2/3  C) 40  D) 50  E) 83 1/3
yup you need to construct a matrix   X********| Windows'|No Windows'''| total   hardFl****'|50*****''|10*********'|60   Not hardFl*|10******|30*********'|40   Total*****|60******'|40*********'|100   so M percent of the apartments with windows have hardwood floors = 50/60 *100   = 83 1/3   so 83 1/3 is the answer.[/u]
<result>E</result>
50% of the apartments in a certain building have windows and hardwood floors. 25% of the apartments without windows have hardwood floors. If 40% of the apartments do not have hardwood floors, what M percent of the apartments with windows have hardwood floors?