Question

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?
Answer
288
112
432
360

Answer 1

360

Answer 2

x = 0.8x + 72
x - 0.8x = 72
0.2x = 72
x = 72/0.2
x = 360