Question

What is $9 ; 10 percent increase

Answer 1

First you turn the % into decimal (.10)
then you multiply .10 by 9 (.90)
if its increase you add .90 to 9$ (9.90$)
the final answer is 9.90$
:)

Answer 2

For this case we can make the following rule of three:
 $ 9 ---------------> 100%
 x -----------------> 110%
 From here, we must clear the value of x: 
 We have then:
 $x = (110/100) * (9) x = 9.9$
 Answer:
 $ 9 plus 10% increase results in:$x = 9.9$