Final answer:
To find the number of days with equal cost, you equate two cost equations and solve for the variable d using algebraic methods, such as subtracting constants from both sides of the equation and combining like terms.
Step-by-step explanation:
To find the number of days, d, for which the cost will be the same, you would set the two cost equations equal to each other and solve for d. This process involves algebraic manipulation. When given the system of equations, such as the demand and the supply equation where Qd equals Qs, you adjust the equations to isolate and solve for the variable of interest. For example, if the demand is represented as 16-2P, and supply is represented as 2+5P, you can equate the two: 16 - 2P = 2 + 5P.
To solve for P, you first subtract 2 from both sides of the equation and add 2P to both sides. The resulting step will be: 14 = 7P, which upon dividing both sides by 7, gives you the equilibrium price P. Once you have P, you can back-substitute into one of the original equations to find the quantity, which will also be where the demand equals the supply.