PLEASE HELP ME ASAP.

Step-by-step explanation:

anything whole or complete is designated as 100%.

what is x% of that whole ?

well, we need to multiply the whole with the same factor we need to multiply 100 with to get x.

100×f = x

f = x/100

whole × f = x% of the whole

so, when we are looking for 5%, what did that mean ?

it means that x = 5, and f = 5/100.

therefore, 5% of $13 is

13 × 5/100 = 65/100 = 0.65

so,

basic cost = $13

tax rate = 5%

tax amount = $0.65

and

basic cost = $13

tax amount = $0.65

total cost = 13 + 0.65 = $13.65

as 5/100 = 0.05

we have seen that the tax amount is simply $13×0.05

and when we add the tax amount to the basic cost, we need to add $13×1 (basic cost) to the $13×0.05 (tax amount), and we get as total

total cost = $13×(1+0.05) = $13×1.05 = $13.65

so, the decimal factor we can use directly without going through all the detail above is : 1.05

step-by-step explanation: