The average height of the four Torres towers is 800 feet. If the four Torres towers have a median height of 900 feet, what is the greatest possible height of the shortest building of the four?  Choices
A) 100 feet  B) 300 feet  C) 500 feet  D) 600 feet  E) 800 feet
a1≤a2≤a3≤a4;   The average height of the four Torres towers is 800 feet: a1+a2+a3+a4=4∗800   The median height of 900 feet: a2+a32=900 --&gt; a2+a3=1800   Substitute a2+a3=1800 into a1+a2+a3+a4=4∗80: a1+1800+a4=4∗800 --&gt; a1+a4=1400   To maximize a1a1 we should minimize a4a4. Minimum value of a4a4 is 900 (the median value), thus the maximum value of a1a1 is  1400 - 900= 
<gadget id="calculator"> 1400 - 900</gadget>
<output>500</output>
500.   Answer: 500 feet
<result>C</result>
The average height of the four Torres towers is 800 feet. If the four Torres towers have a median height of 900 feet, what is the greatest possible height of the shortest building of the four?