3/5=1/1-r

I have to solve for r.
I keep getting -2/3. but the answer in the book says -1/3. can u help please?

\text{start with your equation}\\
\frac 3 5 = \frac 1 {1-r} \\

\text{flip both sides} \\
\frac 5 3 = \frac {1-r} 1 \\

\text{simplify the right and subtract 1 from each side} \\
\frac 5 3 - 1= -r \\

\text{divide by -1} \\
-\frac 5 3 + 1 = r \\

\text{simplify left hand side} \\
-\frac 2 3 = r


so, assuming that I've read your initial problem correctly then your answer of -2/3 is correct :) and the book is wrong :mad: . Enter -2/3 as your answer and send your teacher here if (s)he says you're wrong. :)