Marya plans to participate in a 20 km walk-a-thon. To prepare, she walked 4 km on Monday. She plans to increase her walk by 2 km each week until she reaches 20 km. Marya’s calculations: 4 + 2 = 6. 6 + 2 = 8. 8 + 2 = 10. 10 + 2 = 12. 12 + 2 = 14. 14 + 2 = 16. 16 + 2 = 18. 18 + 2 = 20. The equation representing Marya’s calculations is 4 + 2 w + 20. How many weeks will it take Marya to reach her goal of a 20 kilometer walk? 8 9 10 12