PSAT Math : PSAT Mathematics
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Example Questions
Example Question #1 : How To Find The Amount Of Sales Tax
Cynthia buys 2 shirts, each costing $35, a pair of pants for $40 and a belt for $18. At the register the total she owes is $138.24. What is the rate of sales tax in her state?
To find the amount of sales tax, take the difference in the total before and after tax 
Example Question #1 : How To Find The Amount Of Sales Tax
A certain state charges sales tax at a rate of 8.75% per dollar spent. John spends $127.50 total, including tax, on clothes. What was the total price of the clothing before tax was added?
Since we know the total price with tax, we simply need to work backwards to remove the tax from the total price and find the price of the clothing itself. This can be done as follows:
Clothing Price or C = Total price / 1 + tax rate
C = $127.50/(1 + 0.0875) = $117.24
Example Question #2 : How To Find The Amount Of Sales Tax
Jack is at the grocery store. He buys 
Jack's groceries are not taxed, so they cost 
We will add the two together
Example Question #3 : How To Find The Amount Of Sales Tax
Harry, on his first lunch date with Sally, decides to put the entire bill on his credit card. If the bill came to $28 and Harry wants to leave an 18% tip, what is the total amount that he should pay?
To find an 18% increase, multiply by 1.18.
Example Question #4 : How To Find The Amount Of Sales Tax
Lisa just bought a desktop computer. The computer cost $1500, the keyboard cost $100, and the mouse cost $25. If the local sales tax is 7%, what was the total cost of her purchases?
Total Tax = 
Total Cost = Computer + Keyboard + Mouse + Tax =
Example Question #5 : How To Find The Amount Of Sales Tax
Mike spent $30 on food and $50 on non-food products in the supermarket. There's a sales tax of 10% on non-food products only. How much did Mike spend in total at the supermarket?
Since sales tax is only applicable to non-food products only, we can multiply 50 by 1.1 to get the total price of non-food products. In this case, it is $55. Add this value to the $30 spent on food for a total of $85.
Example Question #1 : How To Find Simple Interest
Dan took out a $1200 loan at a rate of 3% simple interest a year. What is the amount of interest accrued for one month?
$1200 is the amount that he took out.
3% annually would yield an interest amount of $36.
Therefore, each month, he would be paying $3 a month.
Example Question #1 : How To Find Simple Interest
Peter wanted to buy a car and borrowed $2,500 from the bank at 5% simple interest per year. He was able to pay back the loan in one lump sum at six months. What was the total amount he paid the bank?
Simple interest is given by 
Remember, six months is the same as half of a year. The total paid back to the bank is the principle plus the interest, or $2,562.50.
Example Question #3 : How To Find Simple Interest
I have $100 in my bank. After one year, I have withdrawn a total of $20 and I still have $85 in the bank. What is the yearly interest rate of my bank account?
Since I have withdrawn $20, that means I only have $80 in my account.
which is 6.25%.
Example Question #2 : How To Find Simple Interest
You really want to buy a car that costs $15,000 but you only have $5,000 saved. Rather than getting a bank loan, your parents offer to lend you the extra money but will require you to pay them back with 4.3% interest. How much will car cost in total after you have paid your parents back?
Amount borrowed = $15,000 – $5,000 = $10,000
Interest of 4.3% = $10,000 * 0.043 = $430
Total cost of car = $5000 + $10000 + $430 = $15,430
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