Prob. of a system can be a failure is less than (1-0.9999) = 0.0001
<span>now probability that the system will be failure when it has x components is </span>
<span>(0.2)^x </span>
<span>so, (0.2)^x < 0.0001 </span>
<span>or, x*log0.2 < log0.0001 </span>
<span>or, x > log0.0001/log0.2 [the sign changes coz log 0.2 is negative] </span>
<span>or, x > 5.7227 </span>
<span>so, the no. of components (x) has to be 6</span>
The answer to your question is 309 times 29 equals 8,961