BMS employs 8 professors on their staff. Their respective probability of remaining in employment for 10 years are 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. The probability that after 10 years at least 6 of them still work in AMS is ?	Choose one
A) 0.19	B) 1.22	C) 0.1	D) 0.16	E) 0.18456
Asking atleast 6 of them continue ,   it has 3 cases.   1 all 8 professors continue.   2 7 professors continue and 1 professors discontinue.   3 6 professors continue and 2 professors discontinue.   1st case all 8 continue is = 2/10*3/10*4/10*5/10*6/10*7/10*/8/10*9/10=9factorial/10power8   =362880/100000000   =&gt;0.00363.   2nd case any 7 professors continue, and 1out of 8 discontinue ,8C1 means 8 ways.   = 2/10*3/10.......8/10*1/10, (9/10 prodbability professor discontinue then 1/10)   in this way if we calculate for 8 possibilities then value is =&gt;0.03733.   3rd case any 6 professors continue and 2out of 8 discontinue , 8C2 means 28 ways.   = 2/10*3/10.....2/10*1/10( 2 professors discontinue.   if we calculate for 28 possibilites P value is=&gt;0.1436   =0.00363+0.03733+0.1436= 
<gadget id="calculator">0.00363+0.03733+0.1436</gadget>
<output>0.18456</output>
0.18456=   0.18456
<result>E</result>
BMS employs 8 professors on their staff. Their respective probability of remaining in employment for 10 years are 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. The probability that after 10 years at least 6 of them still work in AMS is ?