It means that her height in this year is [tex]106\%x[/tex] in regards to the last year, where x is her height in last year, so:
[tex]159=106\%x[/tex]
[tex]159=\frac{106}{100}x[/tex]
[tex]159=\frac{53}{50}x[/tex]
[tex]159*50=53x[/tex]
[tex]159*50=53x[/tex]
[tex]7950=53x[/tex]
[tex]150=x[/tex]