A is 13th from the top, B is 18th from the bottom. When A and B change their position then A becomes 21th from top. What is the new position of B from bottom? 

A tree is seventh in a row of trees from either end of the row. How many trees are there in the row?

Rajan is ranked 11th in the list of successful boys in a class and at 31st from the bottom. Three boys did not take the exam at all and one failed. How many students are there in the class?

Some boys are  sitting in a row. P is sitting fourteenth from the left and Q is seventh from the right. If there are four boys between P and Q, how many boys are there in the row ?

The position of the first and the sixth digit in the number ‘9865474362’ are interchanged, similarly the positions of the second and the seventh digits are interchanged and so on. Which of the following will be the FOURTH digit from the left end after the rearrangement? 

In the class of boys and girls, the rank of Obama is15th and the rank of Shabana is 8th.The rank of Obama is 8th only in boys and Shabana’s rank is 4th only in girls. In the boys and girls, Obama’s rank is 18th from other side. Shabana’s rank is 7th only in girls from other end. Then find the total number of boys in the class. 

In a class, P has more marks than Q and R does not have the least marks. S has more marks than T and T has more marks than P, who among them will have the least marks?