Question is in description Please help me answer

Question

Petrolyn motor oil is a combination of natural oil and synthetic oil. It contains 5 liters of natural oil for every 7 liters of synthetic oil. In order to make 804 litters of petrolyn oil, how many liters of natural oil are needed

Answer 1

5/12 of the mixture is natural

7/12 of the mixture is synthetic

 

(5/12)(804) = 335

Answer 2

Andrea,

 

Let x be the number of liters of natural oil needed. The number of liters of synthetic oil will be 7/5 x, since the ratio of the synthetic oil to the natural oil is given to be 7 to 5.

 

You can now set up an equation:

 

x + 7/5 x = 804.

 

To solve this fast, get rid of the denominators and multiply both sides by 5:

 

5x + 7x = 4020

 

Solve for x:

 

12x = 4020

 

x = 335.

 

The answer is that 335 liters of natural oil are needed.

 

(You should check this answer is correct by using this number in the statement of the original problem.)