A farmer plants corn and wheat on an 180-acre farm. The farmer wants to plant three times as many acres of corn as wheat. How many acres of each crop should the farmer plant?

Let x be the number of acres of corn

let y be the number of acres of wheat

corn and wheat will take up 180 acres

x+y=180

3 times corn than wheat

x=3y

2 equations 2 unknown

x+y=180

x=3y

solving using substitution

x+y=180

substitute for x

x+y=180

(3y) + y=180

3y+y=180

4y=180

divide by 4 to both sides

4/4 y = 180/4

y=45

45 acres of wheat planted

using 2nd equation to find x

x=3y

x=3 (45)

x=135

135 acres of corn planted