Seven songs are to be rendered in a programme. In how many different orders could they be rendered?

Four children are running a race . (i) In how many ways can the first two places be filled ? (ii) In how many different ways could they finish the race ?

The genes controlling the seven pea characters studied by Mendel are known to be located on how many different chromosomes ?

If a matrix contain 5 elements, then how many different orders of matrices are possible ?

The genes controlling the seven pea characters studied by Mendel are now known to located on how many different chromosomes?