In how many ways first and second rank in mathematics, first and second rank in physics, first rank in chemistry, and first rank in English be given away to a class of 30 students.

A class has 30 students. The followign prizes are to be awarded to the students of the class- first and second in mathematics, first and second in Physics, first in Chemistry and first Biology. If N denote the number of ways in which this can be done, then

In how many ways can the following prizes be given away to a class of 20 students: first and second in mathematics,l first and second in chemistry, first in physics and first in English?

In how many different ways the following 5 prizes be distributed among 10 students? First and second in Mathematics; first and second in physics and first in Hindi.

Out of 80 students who secured first class marks in Matchematics or in Physics , 50 obtained first class marks in Mathematics and 10 in both Physics and Mathematics. How many students secured first class marks in Physics only ?

In a class of 45, neha's rank is 15th from first, what is her rank from the last ?

The country which ranks first in the world in generation of wind energy is