How do you know where to place a decimal when fining the value of numbers?

With adding you add the amount of decimals in your problem and that's what you go form and multiplying they go straight down

So don't take my word i'm not exactly a mathematical person but i would assume a. because while selling the soap every month you increase in sells so you would by 11 percent. the you would get the factor 0.89 which if i had to guess would be the monthly profit over 11 probably wrong tho