Question

The sum of three consecutive numbers is 405. What is the 3rd number?

Answer 1

$n+n+1+n+2=405\\3n=402\\n=134\\\\n+2=136$

136

Answer 2

The third number is 136.

Given :

Sum of three consecutive numbers = 405

To find :

The third number

Solution :

Let the first number be x.

As it is said that the three numbers are consecutive, hence the other two numbers will be x+1 and x+2

According to the problem,

=> x + x + 1 + x + 2 = 405

=> 3x + 3 = 405

=> 3x = 405 - 3

=> 3x = 402

=> x = 402/3

=> x = 134

The first number = 134

The second number = x + 1 = 134 + 1 = 135

The third number = x + 2 = 134 + 2 = 136

Hence, the third number is 136.

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