Initial investment on Jan 1, 2013 = (500 shares)*($24 per share) = $12,000
Dividend collected at the end of 2013 = $2.50*500 = $1,250
Dividend collected at the end of 2014 = $4*500 = $2,000
Dividend collected at the end of 2015 = $3*500 = $1,500
Mony received from sellng the 500 shares at the end of 2015 = $20*500 = $10,000
Total returns at the end of 2015 = 1,250+2,000+1,500+10,000 = $14,750
Net gains = 14750 - 12000 = $2,750
Duration = 3 years
Realized total rate of return = 2750/12000 = 0.2292 = 22.9%
Answer: 22.9%