required ans of the below question a construction company is bidding two contract A and B. The probability that the company will get contract A is 3/5 , will get contract B is 1/3 and will get both the contract is 1/8. what is the probability that the company will get contract A or b or Both the contract?
 A: Draw a picture (Venn diagram), by drawing two intersecting ovals. Label one of them $A$, the other $B$. The region where they intersect represents getting both contracts. Write $1/8$ in that region. 
The whole of $A$ has probability $3/5$. So the part of $A$ which is not in $B$ has probability $3/5-1/8$, which is $19/40$. Write $19/40$ in the part of the oval $A$ which is not shared with $B$.
The whole of $B$ has probability $1/3$, so the part of $B$ which is not in $A$ has probability $1/3-1/8=5/24$. Write $5/24$ in the appropriate region. 
Now your picture has all the information you need to solve the problem. You need the combined  probabilities of the three regions you inserted numbers into. It may become clear that we have worked a little too hard, and we could have found the combined probabilities in a somewhat simpler way. 
There is also an "algebraic" approach that presumably will soon be given in an answer. Perhaps you can do the problem both ways to have clearer knowledge of what is going on. 
A: The probability of individual  events satisfies $P(A \text{ or } B) = P(A) + P(B) - P(A \text{ and } B)=3/5+1/3-1/8$
