Solve for independent event

The probability that neither event happens factorizes.

1. The probability that neither happens is $1-0.84=0.16$.
2. By independence, $(1-0.6)(1-P(B))=0.16$.
3. So $1-P(B)=0.16÷0.4=0.4$.
4. Therefore $P(B)=0.6$.

Answer: $0.6$