Question

Question 21

Fill in the blanks to make each statement true:

Three consecutive numbers whose sum is 12 are ......................, ......................., and ........................

Answer 1

3, 4, 5
Let the three consecutive numbers be x, x+1 and x+2.
According to the question,
x+x+1+x+2=12
$\Rightarrow 3x+3=12\Rightarrow 3(x+1)=12\Rightarrow x+1=4\Rightarrow \frac{3(x+1)}{3}=\frac{12}{3}\Rightarrow x+1=4\Rightarrow x=3$
Hence, the consecutive numbers are 3, 3+1 and 3+2, i.e. 3, 4 and 5.