The question goes ,"In a random survey of 1000 people, it is found that 7% have lung problem.Of those who have lung problems,40% are heavy smokers,50% are moderate smokers and 10% are non-smokers.For those who do not have any lung problems,10% are heavy smokers,70% are moderate smokers and 20% are non-smokers.If a person is found as a heavy smoker,what is the probability of that person having a lung problem?"

I don't know how exactly to tackle this problems,any help will be appreciated

I don't know how exactly to tackle this problems,any help will be appreciated