Answer:

60 tiles.
Explanation:
$15.00 per tile plus a flat fee of $378.00 that charges Tile All. 
Therefore, for x number of tiles, the total cost of installation will be 
C = 378 + 15x ........... (1) 
Again, $14.50 per tiles plus a flat fee of $550.00 that charges Kitchen Plus. Amanda has at Kitchen Plus, a 10% discount coupon. 
Therefore, for x tiles installation the charges will be 
 .......... (2) (Answer)
 .......... (2) (Answer) 
Now, if for x number of tiles both the company charges the same, then 
378 + 15x = 495 + 13.05x (From equations (1) and (2)} 
⇒ 1.95x = 117 
⇒ x = 60 tiles. (Answer)