GATE CS 1998 Q1.14 — Combinational Circuits

A multiplexer (MUX) is a combinational circuit that selects binary information from one of many input lines and directs it to a single output line.

The relationship between the number of select lines ($n$) and the number of input lines ($N$) in a multiplexer is given by:

Given that the multiplexer has a $4$-bit data select input ($n = 4$):

Thus, a multiplexer with $4$ select lines has $16$ input lines and $1$ output line, which is a $16:1$ multiplexer.