Question

Nick has some pens and some pencils. The number of pens he has is two less than the number of pencils. Three times the sum of the number of pencils and pens together is 18.

Which equation can be used to find the number of pencils Nick has, x ?

Answer Choices

3(x+2)=18


3(x−2)=18


3(2x+2)=18


3(2x−2)=18

Answer 1

It is 3(2x-2)=18.

Reason: Lets say x is pencils and y is pens. If the number of pens is 2 less than the number of pencils, the equation would be y = x - 2. Next, 18 equals 3 times the sum of x and y (pencils and pens), So the equation would be 3(x + y) = 18. Since you already know that y = x - 2, you can plug that into the equation. So, 3(x + x - 2) = 18. Then you add the two X's together to get, 3(2x-2) = 18.