A Stochastic Search Game

An object is hidden at a point e on the segment $[ {a,b} )$. A searcher tries to locate it by choosing points $x_i $ and asking: Is egreater than $x_i $ ?There is a positive probability of obtaining a wrong answer to these questions. The searcher wishes to locate the object in the smallest set possible in spite of the fact that some of the information that he has obtained may be false.