Answer:
{Monday, Tuesday, Wednesday, Thursday}
Explanation:
First we need to get the complement of B i.e B'
B' are the set in the Universal set but that are not in B
B' = {Monday, Tuesday, Wednesday, Thursday}
A= {Monday, Tuesday, Wednesday, Thursday, Friday}
A intersect B ' are the days of the week that are common to both sets;
A intersect B ' = {Monday, Tuesday, Wednesday, Thursday}