Suppose you have a project that has a $0\mathrm{.}4$ chance of doubling your investment in a year and a $0\mathrm{.}6$ chance of halving your investment in a year. What is the standard deviation of the rate of return on this investment?

Note: Do not round intermediate calculations. Enter your answer as a percentage rounded to $2$ decimal places.

Standard deviation

$0\mathrm{.}40\%$