The president of a company gave two talks, one on Monday and one on Tuesday. A total of 405 employees attended the Monday talk, 275 attended the Tuesday talk and 55 went to both. How many employees attended at least one of the talks

625 employees

Explanation:

Given that,

Let the Monday talk be A and the Tuesday talk be B,

Employees attend Monday talk: I A I = 405

Employees attend Tuesday talk: I B I = 275

Employees attend both talks: I A ∩ B I = 55

Employees attended at least one of the talks: I A ∪ B I

= I A I + I B I - I A ∩ B I

= 405 + 275 - 55

= 625