Will Mark Brainliest ONLY IF You Show Work! Due At 11:59. Please Help!

Riley runs against the wind at a velocity of 2.0 m/s for 4.0 s, then turns around to get her lunch and runs with the wind at her back at 4.0 m/s for 4.0 s. Use positive values for against the wind and negative values for with the wind at his back. What is the average velocity in m/s of Riley during the 8.0 second time interval?