Ratios and Rates - Basic Math

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.

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.

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 .

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 .

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.

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.

The team has won 5 games.

The number of played games is 25.

Therefore, the ratio of winnings to the total is:

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:

Since there are 3 feet to a yard, multiply the number of yards by 3.

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:

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:

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.

First you find the total amount of sales that Sara made this week by selling six lamps at $200 a piece:

Sara gets a 6% commission on her sales, so next you find what 6% of 1,200 is:

So, Sara makes $72 from commission this week. However, we can't forget about the $500 weekly salary she also gets! We add her week's commission plus weekly salary to find the total amount she makes during this particular week:

There are 24 hours in a day. To find out how many days are in 432 hours, divide that value by 24, the total number of hours in a day.

We can interpret the information given in the question as "150 is 8% of some number, or whatever amount Maggie's sale is." We can turn this sentence into algebra by calling "some number" x:

From here, we solve for x by isolating it on one side of the equation:

Maggie's sale was $1,875.

From the information given in the question, we can ask ourselves the following question- $120 is what percent of $670? We can turn this into algebra by calling "what number" x:

From here, we solve for x by isolating it on the right side of the equation:

Rounding to the nearest tenth gives us 17.9, so the final answer is 17.9%.

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.

To find the multiplier, divide two numbers from the same row:

Now, multiply this by and set that equal to

Divide both sides by

To figure out the ratio, divide the second column by the first.

Since we are multiplying the first column by to get the second column, we can set up the following equation for .

Multiply both sides by 7.

To find , we can set up the following ratio:

Now, cross multiply and solve.