Write out an equation for the problem: 

where  represents Juan's age and  represents Mary's age.

Plug in Juan's age: 

Once we multiply, we find that Mary is 8 years old. 

Write an equation for the problem: 

where a represents Ashley's age and  represents Katie's age.

We plug in Katie's age: 

In order to solve for Ashley's age we divide both sides by 3. This will give us Ashley's age:  years old. 

We see that the ratio is 4 students to 2 teachers. Notice there are half as many teachers as there are students.

With this in mind, we can find the number of teachers by dividing the number of students by 2:

 teachers. 

In order to solve this word problem, you have to know the correct geometric equation that is related to it. At that point, you can plug numbers of known values into the equation and solve it by reversing the operations performed on either side of the equals sign until the unknown variable is isolated and defined.

The area of a square is found using the following formula: .

Take the square root of each side.

In order to solve this word problem, you have to know the correct geometric equation that is related to it. At that point, you can plug numbers of known values into the equation and solve it by reversing the operations performed on either side of the equals sign until the unknown variable is isolated and defined.

The area of a circle is found using the following formula: .

Divide each side by pi .

Take the square root of each side.

In order to solve this word problem, you have to know the correct geometric equation that is related to it. At that point, you can plug numbers of known values into the equation and solve it by reversing the operations performed on either side of the equals sign until the unknown variable is isolated and defined.

The volume of a cube is found using the following formula: .

Take the cube root of each side. The cube root is the number that is multiplied by itself three times in order to equal the original number.

In order to solve this word problem, you have to know the correct geometric equation that is related to it. At that point, you can plug numbers of known values into the equation and solve it by reversing the operations performed on either side of the equals sign until the unknown variable is isolated and defined.

The volume of a cube is found using the following formula: .

Take the cube root of each side. The cube root is the number that is multiplied by itself three times in order to equal the original number.

In this proportions problem, you can solve for the cost of each plum in the first case. The problem says 4 plums cost $5.50, so

We can now use the value of x, or the cost of each plum, to calculate the cost of 6 plums.

.

The cost of 6 plums is $8.25.

Explanation:

Step 1: In order to find out how many cookies Jack needs to sell, you first need a formula.

(price/cookie)(number of cookies) = money needed

Step 2: Substitute the known values (price/cookie, money needed)

Step 3: Isolate the unknown variable (number cookies) by dividing both sides by (price/cookie), then solve: