Martha sells dolls at her doll store. If she sells dolls for $55 and there is a 7% sales tax,what is the total cost of the doll

Sales tax means you add whatver the percent of the cost is to the original price to get your final price in this example the solution would just be 

55*7%= 55*.07=3.85

know since we have the amount it costs with the tax we add 55 and 3.85 to get 58.85 after sales tax