To improve the energy efficiency of a house double lay ceiling insulation is to be installed. The total cost for installing the double lay insulatia is the sum of the material costs per unit ($19.59) and the professional installation fee per unit ($8). In addition, a $40 travel fee is charged by the company. (i) Complete the equation below to show how to calculate the total cost of mobile usage for the year. Clearly define the variable that you use. Variable, x= Cost ($) (ii) Use your equation to find out how many units of double lay insulation are needed to fill a roof cavity if the total cost of installation is $4730.30. b) Natalia Romanova is a Marvel Comic book collector who needs to raise funds to buy some rare editions of The Avengers comics. Natalia sells one fifth of her current collection to fund the purchase of 12 rare The Avengers comics. After the transaction Natalia has 88 comics in total. How many comics were in Natalia's original collection? Use algebraic techniques to support your answer and clearly define any variables that you use.
