The sum of five consecutive numbers is 20. What is the sum of first three consecutive numbers ?

The correct answer is Option 2: 9.

Let the five consecutive numbers be represented as:

$x,x+1,x+2,x+3,x+4$

According to the given condition, the sum of these five consecutive numbers is 20:

$\left(x\right)+(x+1)+(x+2)+(x+3)+(x+4)=20$

Combining the terms on the left side of the equation:

$5x+10=20$

Subtracting 10 from both sides:

$5x=20-10$

$5x=10$

Dividing by 5 gives the value of the first number:

$x=2$

So, the five consecutive numbers are 2, 3, 4, 5, and 6.

Now, we calculate the sum of the first three consecutive numbers:

$\text{Sum}=2+3+4=9$

Hence, the sum of the first three consecutive numbers is 9.