You can assume that "clock", "table", and "paper rolls" are variables. You
have three simultaneous linear equations in three variables. They are easy
to solve.
Alternatvely, you can assume that the value of a clock is the hour it shows,
the value of a table is its number of legs, and the value of a set of paper
rolls is the number of rolls. The first three equations are all consistent
with this.
