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?

A.112

B.288

C.360

D.432

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?

 A.112

 B.288

 C.360

 D.432

anonymous · Answer

Put x on the left side. Like this,

x-0.8x=72

Remember that infront of x, you have 1, so do this

1x-0.8x = 72

Now do the math there and you will get your answer.

anonymous · Answer

multiplying by 10 on RHS and LHS,
10x-8x-720=0
2x=720
x=360