Question

Clare asks Andre to play the following number puzzle: Pick a number Add 2 Multiply by 3 Subtract 7 Add your original number Andre’s final result is 27. Which number did he start with?

Answer 1

he started with the number 7.

7+2=9
x3=27
-7=20
+7=27

Answer 2

ANSWER

He started with

`7`


Step-by-step explanation

Let the number be


`x`



When Andre adds 2, the number becomes,


`x + 2`


When he multiplies by 3, the number becomes,



`3(x + 2)`


When 7 is subtracted, he gets,


`3(x + 2) - 7`


When he adds the original number, he gets,


`3(x + 2) - 7 + x`


We now equate all this to 27,




`3(x + 2) - 7 + x = 27`

We expand brackets to get,


`3x + 6 - 7 + x = 27`

Group like terms,

`3x + x = 27 + 6 - 7`
Simplify,


`4x = 28`


`x = (28)/(4)`

`x = 7`


Hence the original number is 7.