Basic Arithmetic : Ratios and Rates
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Example Questions
Example Question #1 : Ratio Tables
Find the value of 
The numbers on the left side to the numbers on the right side are in a ratio of 1 to 7. In other words, multiply the numbers on the left by 7 to get the numbers on the right.
Using that ratio, we arrive at the following equation for x:
Now, divide both sides by 7.
Example Question #1 : Ratio Tables
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Find the value of 
To find 
Now, cross-multiply and solve.
Example Question #2 : Ratio Tables
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Find the value of 
To find the multiplier, divide two numbers from the same row:
Now, multiply this by 
Divide both sides by
Example Question #1 : Ratio Tables
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In the ratio table above, find 
To figure out the ratio, divide the second column by the first.
Since we are multiplying the first column by 
Multiply both sides by 7.
Example Question #2 : Ratio Tables
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Find the value of 
To find 
Now, cross multiply and solve.
Example Question #1 : Linear Equations With Ratios And Rates
I put 
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 #1 : Linear Equations With Ratios And Rates
If 
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 #11 : Ratios And Rates
If a car travels at 
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 #1 : Linear Equations With Ratios And Rates
If one recipe calls for 
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 #1 : Linear Equations With Ratios And Rates
The ratio of boys to girls in a class is 
We can write the following equation using the ratios given:
Now, we can cross multiply to get the following equation:
Now divide both sides by 
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