To divide the 1/4 of a pound into two equal parts, it is necessary to divide 1/4 by 2, as follow:
(1/4)/2
if 2 is written as 2/1, the previous quotient can be written as a product:
(1/4) (1/2) = 1/8
Now, to write a general expression that takes into account the number of siblings, you name the number of siblings as x. Thus, you have:
(1/4)/(x) = 1/(4x)