Question

HELP! There is this question on my test:

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

I keep getting 360! I submitted it and it was incorrect, what am I doing wrong??

Answer 1

288

Explanation:

short and sweet

Answer 2

There are several information's already given in the question. Based on those information's, the answer can be easily deduced.
The equation given in the question is
x = 0.8x + 72
x - 0.8x = 72
0.2x = 72
x = 360
Now
Number of people that became
member of the site = (80/100) * 360
= 288 people
From the above deduction, it can concluded that the correct option among all the options that are given in the question is 288.