Question 30·Hard·Percentages
A store marks up the wholesale cost of a small appliance by to set a regular selling price. During a promotional sale, the appliance is advertised at off the regular selling price, and a sales tax of is applied to the discounted price at checkout. If a customer pays a final total of $59.40, what was the wholesale cost of the appliance, in dollars?
(Express the answer as an integer)
For chained percentage problems (markup, discount, tax, etc.), convert each step into a multiplier of the form , apply them in order, and either combine them into one overall multiplier or work backward by dividing to undo each step. Avoid adding or subtracting the percentages directly; instead, set up an equation like and solve for the original value. This keeps the work organized and minimizes arithmetic mistakes under time pressure.
Hints
Represent the unknown price
Let represent the wholesale cost. How can you write the regular selling price if the store adds a markup to ?
Turn each percentage into a multiplier
Remember: increasing by means multiplying by , and decreasing by means multiplying by . What multipliers correspond to markup, off, and tax?
Combine the multipliers and use the final price
Starting from , multiply by the three multipliers in order to get an expression for the final checkout price in terms of . Set that equal to $59.40 and solve for .
Desmos Guide
Use a single expression to find the wholesale cost
In Desmos, type the expression 59.40/(1.5*0.8*1.1) or equivalently 59.40/1.32. The value that Desmos outputs is the wholesale cost of the appliance.
Step-by-step Explanation
Define the variable and model the markup
Let be the wholesale cost (in dollars).
A markup of means the regular selling price is the original plus half of it:
Model the 20% discount
A discount of means the customer pays of the regular price.
So the discounted price is:
Model the 10% sales tax and set up the equation
A sales tax of means the customer pays of the discounted price, so we multiply by :
We are told this final price is $59.40, so:
Solve for the wholesale cost
Solve the equation from the previous step by dividing both sides by :
Compute this division:
So the wholesale cost of the appliance is .