Recovering an unknown model probability

A parcel service sends a proportion \(p\) of its parcels by route A and the rest by route B. A parcel sent by A arrives on time with probability \(0.90\); a parcel sent by B arrives on time with probability \(0.98\). Overall, the probability that a randomly selected parcel arrives on time is \(0.95\).

Find \(p\), showing how both routes contribute to the overall probability.[4]