The total bill for four friends eating at a restaurant (including tax) is $$\$ 36.00$$. The friends wish to add a \(20 \%\) tip and then to divide the bill evenly among the four of them. How much will each person pay? A. $$\$ 7.20$$ B. $$\$ 9.00$$ C. $$\$ 10.80$$ D. $$\$ 16.20$$

Mastering percentage calculations is crucial in various everyday situations, including financial planning, analysis, and even when dining out. To calculate a percentage of a number, we essentially need to convert the percentage into a decimal by dividing it by 100. This is because the word 'percent' literally means 'per hundred'.

For the math problem we're considering, finding a 20% tip on a $36.00 bill involves multiplying 36.00 by 0.20 (since 20% is equivalent to 20/100, which simplifies to 0.20). It's useful to understand this conversion process because it allows you to easily find any percentage of any number by using the multiplication operation. Consistently practicing this method will make you adept at quickly figuring out sales tax, discounts, interest rates, and tips without relying on a calculator.

Splitting costs among a group is a common scenario in daily life. Whether you're sharing a meal, dividing costs of shared services, or budgeting for a group event, understanding how to divide expenses fairly is extremely important.

To divide expenses evenly, simply sum up the total cost and then divide it by the number of individuals sharing the expense. In our math problem, after adding the tip to the original bill, the next step is dividing the new total by four—the number of friends. The concept of dividing expenses guarantees that each participant bears an equal portion of the costs, ensuring fairness and transparency in financial matters. This mathematical skill is a key part of personal finance and is also employed in various business contexts, including splitting profits, costs, and investments.

Being able to accurately calculate a tip is a social skill that reflects acknowledgement for service received. To compute a tip, first decide on the percentage of the total bill you wish to offer as a tip. Common percentages range around 15% to 20% for satisfactory to excellent service.

Once you have determined the percentage, convert it into decimal form and multiply it by the total bill amount to find the tip. Remember to add the calculated tip back to the original bill to find the new total amount that needs to be paid. In our exercise, the 20% tip shows appreciation for the service at the restaurant and is distributed evenly exactly like the rest of the bill, maintaining fairness among the friends.