# Percentages in Word Problems

Hi, and welcome to this video lesson on percentages in word problems.

I know word problems are most people’s worst nightmare, but never fear, we’re going to learn how to turn a big, scary, word percentage problem into a 3-step breeze!

Okay, let’s look at our problem:

The bill for dinner is $62.00. The diners decide to leave their server a 20% tip. Determine the total cost of dining at the restaurant, including tip. Okay, so what is our goal? We always want to understand the goal in a word problem. Our goal here is: “Determine the total cost of dining at the restaurant, including tip.” That means finding the cost of the meal and finding the cost of the tip so we can add them together. We already know the bill for dinner, so we’re halfway home. Let’s solve the rest of this problem in three easy steps. STEP 1: Change the percentage to a decimal. Remove the % sign from the 20% and drop a period in front of the 20 so we have .20. We are allowed to do this because when we are finding percents, we are really multiplying a decimal number against another number. This is because 20 percent of a number can be written as a ratio of a part per hundred: $$20\% = \frac{20}{100}=.20$$ STEP 2: Multiply the bill by 0.20 to find the amount of the tip: $$62.00(0.20)=12.40$$ STEP 3: Add the tip and bill to find the total. The total cost of dining will be the sum of the bill for dinner and the tip: $$62.00+12.40=74.40$$ The total cost is$74.40.

I hope that helps. Thanks for watching this video lesson, and, until next time, happy studying.

## Practice Questions

Question #1:

Lauren went to her favorite taco truck for lunch. Her bill was $24.80, and she wants to leave a 20% tip. Help Lauren determine what her tip should be. Tip$4.80

Tip $4.96 Tip$4.12

Tip $4.04 Answer: The correct answer is Tip$4.96.
In order to calculate Lauren’s tip, we need to determine what 20% of $24.80 is. Let’s convert 20% to a decimal, which would be 0.20. Now we can simply multiply $$24.80×0.20$$ in order to determine the tip. $$24.80×0.20=4.96$$ Question #2: Michael wants to mow lawns in order to make some extra money this summer, but he needs to find a lawn mower to use. Michael’s brother tells him that he will loan Michael his lawn mower if he gives him 4% of the money he makes on each lawn. If Michael agrees, and he earns 40 dollars on his first lawn mowed, how much money does he own his brother?$2.24

$2.50$1.90

$1.60 Answer: The correct answer is$1.60.
In order to calculate 4% of 40, we need to convert 4% to a decimal. 4% is 0.04 as a decimal. Now we can multiply 0.04 and $40 in order to determine what Michael owes his brother. $$0.04×40=1.6=1.60$$ Question #3: In a study of 250 high school students, 90% of students have taken the drivers education course. How many students have not taken the course? 15 students 20 students 25 students 30 students Answer: The correct answer is 25 students. 90% of the students have taken the drivers education course, and there are 250 students total. Let’s start by determining how many students have taken the course. To do this we can multiply $$0.9×250$$ which equals 225. This means that 225 students have taken the course. If 225 students have taken the course, and there are 250 students total, we can find the difference between 225 and 250 in order to determine how many students have not taken the course. $$250-225=25$$ students have not taken the course. Question #4: Julian scored 90% on his math test. The test had 60 questions. How many questions did he answer correctly? 48 52 54 56 Answer: The correct answer is 54. If Julian answered 90% of the questions correctly, and there were 60 questions total, we can calculate 90% of 60 in order to determine how many questions he answered correctly. Let’s convert 90% to a decimal (0.9), and then multiply this by 60. $$0.9×60=54$$ questions answered correctly Question #5: A video game costs$45 before tax. If the sales tax is 5%, what will the total cost of the game be including tax?

$47.25$45.80

$49.50$48.75

The correct answer is $47.25. Let’s first calculate the tax. If the game costs$45 and the tax is 5%, we can multiply $$45×0.05$$ in order to determine the tax. $$45×0.05 = 2.25$$, which means there will be a \$2.25 tax on the purchase. Now let’s add this tax to the price of the game in order to calculate the total cost of the game plus the tax.
$$45+2.25=47.25$$