Time weighted return problem in the CFAI text (Reading #6) page 137, question 7. The text says the time weighted return for Luongo is 4.77 percent. According to the solution set the holding period returns for year 1=15% and year 2= -4.55. I know this is simple but I can’t quite see how they got to the final answer. TWR should be square root of the product: square root of (1.15)*(-1.0455). The anwer I get is NOT 4.77% but more like 9.6%…??? Did NOT see this question on the Oct. Errata. Any help would be appreciated.

You are doing the math wrong. It is: SQRT(1.15*(1-.0455)) - 1 = 4.77%

No, you were wrong, it is [(1+0.15)*(1+(-0.0455))]^1/2 - 1=0.0477