For this you want to find the price per unit. $12.24/8=$1.53. That means $1.53 per ounce of smoked salmon.
For 5, figure out how many tiles you can fit in the room. Use the expression "$0.84(12*16/4) to figure out the total cost.
For six, repeat the process explained in number 4 to figure out which pack costs less per bottle.
ex. 6-pack is 43 cents per bottle; 8-pack is 38 cents per bottle. Therefore, the pack of eight is a better deal. (This is NOT the answer.)