I would just like someone to check maths for this venn diagram, just to make sure I have done the calculations correct. I have attached copy, with the numbering inside the diagram. I will show my working here. Question: One of 36 tourists on holiday in Namibia and South Africa is chosen at random. The probability that he has been to south africa before is 1/2 The probability that he has been to Namibia before is 4/9 The probability that he has been to neither country before is 1/3 So here is how I worked it out: I convert all the fractions to percentages and add them together: 1/2 = 0.50 = 50% 4/9 = 0.44444 = 44.4% 1/3 = 0.33333 = 33.3% I the add the fraction or percentages up which gave me: 127.777777778. I then did 36/100 = 0.36*127.777777778, which gave me 46.0000000001; I rounded this number to 46. I then took 46-36 = 10, this gave me the intersection of the two circles. Once I had done this, I took 1/2 of 36, 4/9 of 36, which respectively gave me 16 and 18. So I then went on and did 16-10=6 so 8 people went to Namibia, 18-10 = 8 people went to south Africa. This gives me a grand total of 24. I then did 36-24 = 12 people which have not been to either. I did double check with the 1/3 of 36 which is correct. I would appreciate if someone could take a look just to make sure this is correct method.