If set D is a subset of set E, then which of the following is true?
1)D ∩ E = D
2)D ∩ E = E
3)D ∩ E = Ø
plezzzz helpp

Question

If set D is a subset of set E, then which of the following is true? 
1)D ∩ E = D
2)D ∩ E = E
3)D ∩ E = Ø 
plezzzz helpp

john_es · Answer

The first one is the only possible.

anonymous · Answer

how do you do that

john_es · Answer

Intersection means that you have to choose the elements that are in both sets of the intersection operation. If D is a subset of E, then the elements of D must be in E, but in the intersection you only choose those that are in both at the same time, so D is the solution. You suppose D is smaller than E, in the sense that is a subset, so there are elements in E that not are in D, so you choose D.

john_es · Answer

For a more detailed explanation, see http://en.wikipedia.org/wiki/Intersection_%28set_theory%29