SmileyKing wrote:

Hello

Can some one help with this sum please.

a teacher's salary was $4400 after an increase of 10%. what would her salary have been if he had receive an increase of 15%.

how do you work this ...

Let me see if I can break this out into some steps:

You know what the teacher's salary is after a 10% increase. What you need to solve for is the teacher's salary before the 10% increase. So the equation is set up like this:

(1.10)(x) = $4400, where x=teacher's salary before the 10% increase

Solving for x, you get x = $4000

Now the question asks for what the teacher's salary is after a 15% increase. At this point you know the original salary (solved above), so the equation looks like:

New Salary = (1.15)(4000)

New Salary = $4600

You used the equation 1.15x = $4000, which is saying that a 15% increase to the salary of x is $4000. You have your terms mixed up.