Question 260059
question a
add up all the people smokers , non smokers etc=1018
find the number of light smokers and subtract light smokers from total 
divide number of non light smokers by total people that fraction is the probability
there are 74 light smokers
there are 1018 total people
1018
- 74
944

944/1018 is your probability
I am sure the fraction can be reduced.
question b
We are now dealing with only non smokers
870 are non smokers
438 are women non smokers
438/870 is your answer

question c
31/1018 are heavy smokers
31/1018=m/13000
solve for m