1. **Problem a:** Find the probability that a worker with a laptop is connected to router A given $P(A) = 0.9$ and $P(L) = 0.45$. 2. The probability of a worker having a laptop and being connected to router A is the product of the probabilities since these events are independent: $$P(L \cap A) = P(L) \times P(A)$$ 3. Substitute the values: $$P(L \cap A) = 0.45 \times 0.9 = 0.405$$ 4. So, the probability that a worker with a laptop is connected to router A is $0.405$ or 40.5%. 5. **Problem b:** Given $P(L) = 0.45$, $P(D) = 0.30$, and $P(L \cap D) = 0.18$, find the percentage of those who have a desktop that also have a laptop. 6. We want to find $P(L|D)$, the conditional probability that a worker has a laptop given they have a desktop. The formula is: $$P(L|D) = \frac{P(L \cap D)}{P(D)}$$ 7. Substitute the values: $$P(L|D) = \frac{0.18}{0.30} = 0.6$$ 8. Convert to percentage: $$0.6 \times 100 = 60\%$$ 9. Therefore, 60% of those who have a desktop also have a laptop.