The cheerleading coach is ordering new uniforms. There are 4 cheerleaders who need a size 2, a certain number who need a size 6, and half that number who need a size 12. If there are 19 cheerleaders total, how many cheerleaders need a size 6?
Let s be the number of cheerleaders who need a size 6 and t be the number who need a size 12. We know that s = 2t and s + t + 4 = 19.
Substituting the first equation into the second equation, we get 2t + t + 4 = 19
Combining like terms, we get 3t + 4 = 19
Subtracting 4 from both sides, we get 3t = 15
Dividing both sides by 3, we get t = 5
Substituting that value back into the equation s = 2t, we get s = 2 * 5 = <<2*5=10>>10
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Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
You are solving math problems. Here are some examples of how to solve the task:

Mr. Finnegan has 3 tanks with a capacity of 7000 gallons, 5000 gallons, and 3000 gallons, respectively. If he fills the first tank up to 3/4 full, the second tank with water up to 4/5 of its capacity, and the third tank up to half of its capacity, how many gallons in total are in the tanks?The capacity of the first tank is 7000 gallons, and if it is filled up to 3/4 full, it carries 3/4*7000 = 5250 gallons.
When the second tank is filled up to 4/5 of its capacity, it carries 4/5*5000 = <<4/5*5000=4000>>4000 gallons.
The total amount of water in the first two tanks is 5250+4000 = <<5250+4000=9250>>9250 gallons.
If Mr. Finnegan fills the third tank with water up to half its capacity, the tank fills up with 1/2*3000 = <<1500=1500>>1500 gallons.
In total, the three tanks have 9350+1500 = <<9350+1500=10850>>10850 gallons of water.
#### 10850[END]

LaKeisha is mowing lawns to raise money for a collector set of books. She charges $.10 for every square foot of lawn. The book set costs $150. If she has already mowed three 20 x 15 foot lawns, how many more square feet does she have to mow to earn enough for the book set?She has mowed 900 square feet because 3 x 20 x 15 = <<3*20*15=900>>900
She has earned $90 because 900 x .1 = <<900*.1=90>>90
She has to earn $60 more dollars because 150 - 90 = <<150-90=60>>60
She has to mow 600 more square feet of lawns because 60 / .1 = <<60/.1=600>>600
#### 600[END]

Now, solve this next question in the style of the above examples:

The cheerleading coach is ordering new uniforms. There are 4 cheerleaders who need a size 2, a certain number who need a size 6, and half that number who need a size 12. If there are 19 cheerleaders total, how many cheerleaders need a size 6?

### Response:
Let s be the number of cheerleaders who need a size 6 and t be the number who need a size 12. We know that s = 2t and s + t + 4 = 19.
Substituting the first equation into the second equation, we get 2t + t + 4 = 19
Combining like terms, we get 3t + 4 = 19
Subtracting 4 from both sides, we get 3t = 15
Dividing both sides by 3, we get t = 5
Substituting that value back into the equation s = 2t, we get s = 2 * 5 = <<2*5=10>>10
#### 10