  Afshar et al. claim that their experiment shows a violation of the
complementarity inequality. In this work, we study their claim using a modified
Mach-Zehnder setup that represents a simpler version of the Afshar experiment.
We find that our results are consistent with Afshar et al. experimental
findings. However, we show that within standard quantum mechanics the results
of the Afshar experiment do not lead to a violation of the complementarity
inequality. We show that their claim originates from a particular technique
they use to analyze their results. In their analysis, they assume a classical
concept, that particles have a definite trajectory before detection, thus, they
obtain which-way information by particle detection plus path extrapolation by
applying momentum conservation. This analysis technique is standard in
experimental particle physics. Important discoveries such as the detection of
vector bosons have been made through the application of this technique. We note
that particle detection plus path extrapolation is a suitable technique within
de Broglie-Bohm theory of quantum mechanics.
