Olivia spent $20.00 on pencils and pens. Each pencil cost $2.00, and each pen cost $2.50. Which equation represents the number of pencils, x, and the number of pens, y, Olivia could have bought?x+y=20

x + y = 20 ,

x+y=4.50

x + y = 4.50 ,

2x+2.50y=20

2 x + 2.50 y = 20 ,

2.50x+2y=20