There are various cases possible that are as follows
a) Say P execute First and then Q (All statement of P are one after one and same to that of Q) here we have a=8 and b=4;
b)Say Q execute First and then P(same as above ) here we have a=2 and b=6;
c)Say P execute its 1st stmt then Q his 1st then P his 2nd then Q his second..here we have a=8 and b=6;
d) Say P his 1st then Q his 1st and 2nd then P his 2nd here we have a=8 and b=12..
e)Say Q execute its 1st stmt then P his 1st then Q his 2nd then P his second..here we have a=8 and b=12;..
So all aboves are possible out cotcomes if we Run the program in parrallel case as per given Conditions..
f)Say Q his 1st then P his 1st and 2nd then Q his 2nd here we have a=8 and b=6