A chef plans to mix 100% vinegar with Italian dressing. The Italian dressing contains 7% vinegar. The chef wants to make 310 milliliters of a mixture that contains 19% vinegar. How much vinegar and how much Italian dressing should she use?

Amount of  vinegar. 100% : 20 milliliters

Amount of  Italian dressing: 140 milliliters

Step-by-step explanation:

Let's call A the amount of  vinegar. 100%

Let's call B the amount of  Italian dressing . 12% vinegar

The resulting mixture should have 23%  vinegar, and 160 milliliters.

Then we know that the total amount of mixture will be:

Then the total amount of pure antifreeze in the mixture will be:

Then we have two equations and two unknowns so we solve the system of equations. Multiply the first equation by -1 and add it to the second equation:  We substitute the value of B into one of the two equations and solve for A.

Answers:

Number 19: 420 / 14 = 30 words per minute

Number 20: im not sure  

Number 21: 14

Number 22: 80 / 2 = 40 boxes.  40 boxes / 10 = 4 candy per box

6 hours x 40 = 240 boxes. 240 x 4 = (960 candy in 6 hours)