Tough and Tricky questions: Probability.
Medical analysts predict that a quarter of all people who are infected by a certain biological agent could be expected to be killed for each day that passes during which they have not received an antidote. What fraction of a group of 1,000 people could be expected to be killed if infected and not treated for three full days?
Choose the most appropriate option:	A) 16/81	B) 37/64	C) 2/3	D) 19/27	E) 65/81
At the end of each day we will have 3/4 alive. So after 3 days we will have (3/4)^3 people alive. Therefore, fraction of dead people will be 1-(3/4)^3=37/64.   The correct answer is 37/64.
<result>B</result>
Tough and Tricky questions: Probability.
Medical analysts predict that a quarter of all people who are infected by a certain biological agent could be expected to be killed for each day that passes during which they have not received an antidote. What fraction of a group of 1,000 people could be expected to be killed if infected and not treated for three full days?