Your grandmother gives you $4000 for your birthday, which you invest in a mutual fund on January 1. On June 1, your fund balance is $7800, and you then deposit $1200 (which you received for your high school graduation). On the following January 1, you calculate that your dollar-weighted rate of return (using simple interest) for the year was 29.1%. What was your time-weighted rate of return for the year?