Pre-Algebra : Word Problems with One Unknown
Study concepts, example questions & explanations for Pre-Algebra
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Example Questions
Example Question #31 : Word Problems
A new shirt costs 
First, convert the tax percentage into its decimal by dividing by 
Next, find what the tax is on the shirt by multiplying its cost by the value you found above for the tax:
Finally, add the tax to the pre-tax cost of the shirt:
Example Question #32 : Algebraic Equations
The sum of three consecutive even numbers is 96. What is the largest number?
- 6 -6
/3 /3
Largest Number = 34
Example Question #31 : Algebraic Equations
Scotty went to the store to buy some extra baseballs for batting practice. He bought 2 dozen baseballs to add to the number of baseballs he already has. After batting practice, half of his total number of baseballs goes missing. He now only has 32 baseballs left. Based on this information, how many baseballs did he start with?
2 Dozen = 24
32 = half
64 = total number he had after he bought the 2 dozen
64 - 24 = 40 which is the amount Scotty started with
Example Question #33 : Word Problems
Suppose Tina makes 
Write an equation using 
An hour has 60 minutes.
Substitute 
Tina will make 900 ribbons in an hour.
Example Question #32 : Algebraic Equations
Suppose Billy makes 5 nuggets every day from working. How many nuggets will he have after 45 days?
Let 
To find out the total amount of nuggets Billy will make after 45 days, substitute this number into 
Billy will make 225 nuggets after 45 days.
Example Question #34 : Word Problems
Mary had a little lamb. Every three days, she earns another small lamb. How many little lambs will Mary have after 
Write an equation to represent the lambs she will earn after every three days.
Let 
Substitute the number of days to find out how many lambs Mary has.
However, remember that Mary already had a little lamb, which means the total number of sheep she will have will be one more than the total number of sheep after 
The answer is :
Example Question #37 : Algebraic Equations
It costs $49 to rent a moving truck and it costs $0.75 per mile that you travel. Write the equation for the total cost of renting the truck and driving 
When renting a truck, it doesn't matter if you drive 0 miles or 100 miles it will still cost you the rental charge. In this case it was $49. Every mile you drive it costs you $0.75. The cost for 
Example Question #33 : Algebraic Equations
Jazmine went shopping and bought a shirt and shoes. She paid $12 for the shirt. If the total bill was $29, how much did the shoes cost?
When you have an unknown value, replace that value with a variable. In this case, the cost of the shoes is unknown. We know that the total cost of the shirt and the shoes equals $29, so we can write the equation.
To solve for x, we subtract 12 from both sides. We get
So, the cost of the shoes is $17.
Example Question #39 : Algebraic Equations
John wants to buy a car for that costs $26,790. He works in a restaurant for 23 hours a week, where he makes $9.50 per hour. He also works as a tutor, where he makes $19 an hour. What is the minimum number of hours John must work as a tutor each week in order to be able to afford the car in 40 weeks?
The following equation can be set up to reflect the information in the problem, with 
Simplifying gives the following:
We must then isolate 
Therefore, John must tutor for a minimum of 
Example Question #32 : Algebraic Equations
You go to the store and buy apples. The apples cost $0.14 each. The cashier rings up your apples and says your total is $1.12 . How many apples did you buy?
9 apples
4 apples
8 apples
10 apples
12 apples
8 apples
To solve, we will create an equation. We don't know how many apples we bought. When we don't know the value of something, we assign it a variable. so, the number of apples we bought will be x. Now, we know each apple cost $0.14. We can write this as
We also know that the total cost of the apples equals $1.12. We can write this as
Now, to solve for x we divide both sides by 0.14. We get
Therefore, we bought 8 apples.
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