Posted by TIa on .
I rent out 2/5 of my books, give 3 away, buy 9 and now have 27. How many did I start with  I know it's 35 but I can't make the formula work

algebra 
drwls,
let X be the number you start with.
3X/5 3 +9 = 27
3X/5 = 21
3X = 105
I don't see a problem getting 35.