paradox
<a href="https://scienceres-edcp-educ.sites.olt.ubc.ca/2012/08/01/monty-hall-problem/" title="Monty Hall Problem"><img src="https://scienceres-edcp-educ.sites.olt.ubc.ca/files/2012/08/sec_math_probability_montyhall-150x150.jpg" alt="Monty Hall Problem" class="thumbnail thumbnail " /></a>