The first thing you should do in this case is to calculate the floor area.
We have then:
A = (12) * (14) = 168 feet ^ 2
Therefore, since each tile is 1feet ^ 2 then the cost for 168 tiles is:
(168) * (3.50) = $ 588
answer:
the cost of covering the floor with square foot tiles costing $ 3.50 per tile is $ 588