All Basic Arithmetic Resources
Example Questions
Example Question #61 : Basic Arithmetic
I put in a bank account at a annual simple interest rate. How much interest will have accumulated after two years?
This is a simple interest rate problem, for which we use the formula:
Interest = P x r x t
P is the principal, or original loan amount; r is the annual interest rate; and t is the number of years in question.
In this problem, P = $9,000; r = 4%; and t = 2 years. Plugging these into the formula gives us:
So, after two years the account has gathered $720 in interest.
Example Question #14 : Ratios And Rates
If painters can paint houses in day, how many painters would it take to paint houses in day?
We can set up the following proportions using the given information:
Now, cross multiply these two fractions to get the following equation:
Divide both sides by .
Example Question #15 : Ratios And Rates
If a car travels at miles per hour, how many hours would it take the car to travel miles?
We can write 40 miles per hour as the following fraction:
Since we want to figure out how many hours it takes a car to travel 200 miles, we can write the following equation:
Now, cross multiply.
Divide both sides by 40.
Example Question #16 : Ratios And Rates
If one recipe calls for eggs to make waffles, how many eggs are needed to make waffles?
To solve this problem, we can set up a proportion.
That proportion will tell us how many eggs go into each waffle. Since the number of eggs that goes into each waffle doesn't change, we can set these two proportions equal to each other.
Now, fill it in with the information we know:
For the sake of making math easier, drop the words so we get the following equation:
To solve for x, cross-multiply this equation.
Divide both sides by 18.
Example Question #17 : Ratios And Rates
The ratio of boys to girls in a class is . If there are boys in the class, how many girls are in the class?
We can write the following equation using the ratios given:
is the number of girls in the class.
Now, we can cross multiply to get the following equation:
Now divide both sides by .
Example Question #21 : Ratios And Rates
Jessica fills an aquarium with water. The aquarium can hold gallons of water—it's a huge aquarium! The faucet fills the tank at a rate of 1 gallon every 10 seconds. How long (in seconds) will it take Jessica to fill the tank?
The rate at which Jessica fills the tank can be written as a ratio:
Multiply this ratio by the total amount of gallons possible to get the amount of time it takes to fill the tank.
Gallon units cancel out, so you are left with seconds as the final unit in the answer.
Example Question #1 : Other Ratios And Rates
A diving team swims in competitions, and wins overall competitions. What is their lose to win ratio?
A diving team that wins 6 competitions out of 10 will have 6 winning meets and 4 losing meets. Therefore, their lose to win ratio is:
This can be reduced to:
Example Question #2 : Other Ratios And Rates
A soccer team wins out of their games. What is their win to loss ratio?
Since the soccer team has won 8 out of 10 games, they have 8 winning games and 2 losing games.
Therefore, their win to loss ratio is:
This ratio can be reduced to:
Example Question #3 : Other Ratios And Rates
The sales tax rate at your favorite clothing store is . You buy a shirt for and a hat for . What is the total amount, including tax, that you pay for your purchases?
First, you want to figure out the total cost of your purchase by adding up the price of all the items you are buying:
Then, you find the tax you will pay on this total by taking 7% of $35:
You add the cost of your purchase plus the tax to find the total amount that you have to pay:
Example Question #4 : Other Ratios And Rates
Joe takes home a commission of his total sales at the furniture store. Yesterday he sold one chair and two chairs. How much money did he make from commission yesterday?
First you find the total amount of sales that Joe made yesterday by adding the cost of each item he sold:
Joe sold $20,000 worth of furniture yesterday. He makes 15% commision, so we find 15% of 20,000:
Joe made $3,000 from commission yesterday.