probability question

[irish83]

town's flood defences consist of two levees, A and B, and two culverts, C and D. Each of these, independently of the others, may fail with probabilities 0.16, 0.21, 0.35 and 0.42 respectively.


Find the probability that at least one of the culverts will work.


Could anyone point me in the right direction? Older student here can't remember stuff from school.

Thanks

 

[Ishuda]

town's flood defences consist of two levees, A and B, and two culverts, C and D. Each of these, independently of the others, may fail with probabilities 0.16, 0.21, 0.35 and 0.42 respectively.


Find the probability that at least one of the culverts will work.


Could anyone point me in the right direction? Older student here can't remember stuff from school.

Thanks

The best way to approach problems of this sort [at least 1 will ..] is sometimes to approach it from the other end [all will] and use
P(A) = 1 - P(NOT A)
NOT A in your case is all will fail.