The sum of three consecutive number is fifty seven. Find the numbers.

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lemjay's profile pic

lemjay | High School Teacher | (Level 3) Senior Educator

Posted on

Let x be the first number. So, the second and third numbers are represented by the expressions x+1 and x+2, respectively.

Then, to set-up the equation, take the sum of these three numbers.

`x + (x+1)+(x+2)=57`

Simplify the right side of the equation.

`3x+3=57`

And, isolate the x.

`3x=54`

`x=18`

So, the first number is 18. And the second and third numbers are:

second number `= x+1=18+1=19`

third number `= x +2 = 18+2= 20`

Therefore, the three numbers are 18, 19 and 20.

aishukul's profile pic

aishukul | Student, Grade 10 | (Level 3) Honors

Posted on

You can call the first consecutive number as x. The second will be x+1. The third will be x+2. Because the sum of the three numbers is 57 you can set up the equation as follows: 

x + (x+1) + (x+2)=57

3x+3=57

x=18. Now you know the first number. The second number is simply 18+1=19. The third is 18+2=20. Thus: 18, 19, 20 are the three consecutive numbers. :)

prathyuk99's profile picture

prathyuk99 | (Level 1) eNoter

Posted on

The three consecutive numbers can be written as x, x+1, x+2

since they all add up to 57, you must form your equation as x+x+1+x+2=57

solve for x, then add 1 and 2 to the number to get x+1 and x+2

Wiggin42's profile pic

Wiggin42 | Student, Undergraduate | (Level 2) Valedictorian

Posted on

Three consecutive numbers can be written as 

n, n+1, n+1+1= n+2

We are told that the sum of these numbers is 57:

n + n + 1 + n + 2 = 57

Simplify and solve for n. 

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