Question

the probability that the bulb will wait longer than 800 hours is 0.2 we have 3 bulbs in the hall way what is the proability that after 800 hours of service at least one of them will still work? ​

Answer 1

I understand that in calculating the probability that at least one light bulb is still working is equal to 1−P(all light bulbs fail).

Answer should be: 1−(1−0.2)(1−0.2)(1−0.2)=0.488