If the length of a rectangle is increased by 24% and its breadth is decreased by 10%, then by what per cent will the area of the rectangle be increased/decreased?

The average age of six students of a class was 17.5 years. When one student left the class the average age became 16 years. What is the age of the student who left the class?

A dealer sold a DVD player at a loss of 7%. Had he sold it for Rs. 234 more, he would have gained 11%. For what value should he sell it in order to gain 16%?