In a certain country, approximately 22 out of 100 people over the age of 12 smoke. how many smokers would you expect in a group off 550 people over the age of 12?

121 smokers

Step-by-step explanation:

This can be calculated as a simple rule of 3.

In these problems, the first step is identifying the measures in the problem. Then, we must identify whether their relation is direct or inverse.

When it is direct, as one measure increases, the other will increase too.

When it is inverse, as one measure increases, the other will decrease.

In this problem, the measures are the number of people over 12 that smoke, and the total number of people over 12. Their relation is direct, because as the number of people increases, the number of smokers will increase too.

So we must solve the following rule of three:

22 smokers - 100 people

x smokers    - 550 people

x = 550*22/100

x = 22*5.5

x = 121 smokers.

So,  in a group off 550 people over the age of 12, there are 121 expected smokers.

x^2+4x

Step-by-step explanation:

(3x^2+10x+20)-(6x+11) = 3x^2+4x+9

(3x^2+4x+9)-(2x^2+9) = x^2+4x