Question

Malachy was thinking of a number. Malachy divides by 2, then adds 9 to get an answer of 4. What was the original number?

Answer 1

The number is -10

Explanation:

I will answer this while I read through the question.

Let the number be x

Divide by 2

`(x)/(2)`

Add 9 to it

`(x)/(2) + 9`

It gives 4

`(x)/(2) + 9 = 4`

Now, we solve for x

Collect Like Terms

`(x)/(2) = 4-9`

`(x)/(2) = -5`

Make x the subject

`x = -5 *2`

`x = -10`