1. 
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is: 


6. 
David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors per minute. At the same time, Albert gets on an elevator at the 51st floor of the same building and rides down at the rate of 63 floors per minute. If they continue travelling at these rates, then at which floor will their paths cross ? 


9. 
Free notebooks were distributed equally among children of a class. The number of notebooks each child got was oneeighth of the number of children. Had the number of children been half, each child would have got 16 notebooks. Total how many notebooks were distributed ? 

