human
Carson is covering the high school football field with grass seed. Each square meter needs three times as much seed as fertilizer. If Carson uses 60 gallons of seed and fertilizer combined, how many gallons of seed does he use?
assistant
Define a variable ** Let s be the number of gallons of seed Carson uses and f be the number of gallons of fertilizer. We know that s = 3f and s + f = 60.
Write an equation ** Substituting the first equation into the second equation produces 3f + f = 60
Combine like terms ** Combining like terms, we get 4f = 60
Divide by 4 ** Dividing both sides by 4, we get f = 15
How many gallons of seed does Carson use? ** Substituting that value into the equation s = 3f, we get s = 3 * 15 = <<3*15=45>>45
#### 45