Question

$5pr = 60$
n!/(n-r)!

Answer 1

5 pr = 60

Let the constituting element be on the basis of "n".

Condition given : n!(n-r)!

So, Take G10 = XYZ.

Again, X = Y = 1/Z.
5 × p × r = Z/1 [Where Z = 6×10 = 60]
So, 5 pr = 60 (proved).



The above process of solving is known as the Lekwin process in which an absolute works under the solution.

Answer 2

5 pr = 60

Either, p = 60/5r

Or, r = 60/5p

You have to know the value of either "p" or "r" to calculate the other variable's value.