A social networking site recorded that 80% of the people who became members of the site one month were between 30 and 40 years old. The equation below represents this information, where x represents the total number of people who became members of the site that month:
x = 0.8x + 72
How many people who became members of the site that month were between 30 and 40 years of age?
112
288
360
432