List of top Quantitative Aptitude Questions on Set Theory asked in SNAP

A placement company has to assign 1000 software professionals skilled in Java and .Net to a prospective outsourcing company. It finds that 750 have .Net skills and 450 have Java skills, with some professionals skilled in both. Find the number of professionals who have skills in both Java and .Net.

A survey was conducted of 100 people whether they have read recent issues of 'Golmal', a monthly magazine. Summarized information is presented below:
Only September: 18
September but not August: 23
September and July: 8
September: 28
July: 48
July and August: 10
None of the three months: 24
What is the number of surveyed people who have read exactly for two consecutive months?