There are 1000 students in a school and among them 30 % of them attends chess class. 10% of the students who are in the chess class are also enrolled for swimming. No other students are interested in swimming so how many will attend the swimming class if all enrolled attends?  Pick:
A) 1
B) 10
C) 100
D) 30
E) 20

Rationale: 30 % of 1000 gives 300 . so 300 attends chess and 10 % of 300 gives 30 . so 30 enrolled for swimming answer : d
Answer: D