One of the greatest assets of a secretary is often his/her ability on the keyboard of a computer. Mrs. Garcia has been recognized as the Most Outstanding Typist at a prestigious firm because of her outstanding typing speed. The table below displays data collected from her most recent evaluation.

minutes 1 2 3 4
words 70 140 210 280

Write an equation to represent the total number of words, y, that Mrs. Garcia can type in x minutes