Based on the given information and a sale tax of 5%, the correct equation to find the total cost (t) is: t = 1.05a
How to find the equation that can be used to find the total cost
To find the equation that can be used to find the total cost (t), consider the relationship between the advertised cost (a) and the total cost (t) after sales tax is included.
From the given table:
Advertised cost (dollars) a: 51.00, 163.00
Total cost (dollars) t: 53.55, 171.15
We can see that the total cost (t) is the advertised cost (a) plus some additional amount, which represents the sales tax.
Let's calculate the sales tax for the first item:
Sales tax = Total cost - Advertised cost = 53.55 - 51.00 = 2.55
Similarly, for the second item:
Sales tax = Total cost - Advertised cost = 171.15 - 163.00 = 8.15
Based on these calculations, we can conclude that the sales tax is a fixed percentage of the advertised cost and the fixed percentage is 5%.
Therefore, the correct equation to find the total cost (t) is:
t = 1.05a
This equation accounts for the additional 5% sales tax, which is 0.05 times the advertised cost (a).