Question

Aiden wrote a riddle: Five less than 1/5 times a number is the same as the sum of the number and 1/3. How do you find the number?

Answer 1

The number is `color(green)(-22.5)`

Explanation:

Let the number be `n`

#{: ("Five less than 1/5 times a number: ",1/5n-5), ("is the same as: ",=), ("the sum of the number and 1/3",n+13) :}#

`1/5n-5=n+13`

Multiply both sides by `5`
`n-25=5n+65`

Subtract `n` from both sides
`-25=4n+65`

Subtract `65` from both sides
`-90=4n`

Divide both sides by `4`
`-22.5=n`

Exchange sides (not necessary, but most people like it better this way)
`n=-22.5`