Question

The sum of three consecutive numbers is 30. What are the numbers?

• A. $8$
• B. $9$
• C. $10$
• D. $11$

Answer 1

Answer: (B), (C), (D)

$11$

Let, the numbers are $x,x+1,x+2$
Given that the sum of these three numbers is 30.
$\Rightarrow x+x+1+x+2=30$
$\Rightarrow 3x+3=30$

The unknown is $x$
We need to solve $x$ by isolating it to one side of the equation

Step 1: Subtract 3 from both sides of the equation to eliminate the constant on the left side of the equation.
$3x+3-3=30-33x=27$

Step 2: Now, divide both sides by 3 to eliminate 3 on the left side of the equation.
$\frac{3x}{3}=\frac{27}{3}\Rightarrow x=9$
$\therefore x+1=9+1=10$
and $x+2=9+2=11$

Hence, the numbers are $9,10$ and $11.$