What power if 10 do i have to multiply ti make 1.9 a whole number

Which of the following is the result of expanding

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)

Pls never taught i’m really confused and i rlly need