Final answer:
It takes around 10 years for Matteo's risk of dying from lung cancer to drop to half the risk that Paul faces.
Step-by-step explanation:
The time it takes for Matteo's risk of dying from lung cancer to drop to half the risk that Paul faces depends on several factors, including the duration and intensity of their smoking habits and other individual health factors. However, on average, it is estimated that it takes around 10 years for the risk of lung cancer to drop to half for individuals who quit smoking compared to those who continue smoking.
Learn more about Effect of quitting smoking on lung cancer risk