6. Khalid might have added the variable term 1.2y to both sides of the equation and subsequently subtracted the constant term 6.7 from both sides, thereby isolating the variable term and reaching the equation 1.8=1.2y.
7. To find the number of bottles, subtract the empty pack weight 15/16pounds from the total weight 6 9/16 which leaves 5 10/16 pounds for the water. Next, convert the weight of one bottle 1 1/8 to a fraction with the same denominator, which is 18/16 pounds Finally, divide the total water weight 5 10/16 by the weight per bottle 18/16 which equals 5 bottles.