Question

What are 3 consecutive numbers whose sum is 54?

Answer 1

Another approach

The three number are: 17, 18 and 19

Explanation:

Let the first number be `n`
then we have:
`n+(n+1)+(n+2)=54`

`=> 3n+3=54`

Subtract `color(red)(3)` from both sides

`=>color(green)(3n+3color(red)(-3)=54color(red)(-3)`

but +3-3=0

`=>3n+0=54-3`

Notice that the 3 has changed sides and as a consequence we now have 3n on its own

`=> 3n=54-3`

Divide both sides by `color(red)(3)` to get n on its own

`=> color(green)(3/(color(red)(3))n=54/(color(red)(3))-3/(color(red)(3)))`

But `3/3=1 " so "3/3n` becomes just `n`

`=>n=51/3=17`

So we have :`17+18+19=54`