Problem 13 (1997 AJHSME)

Three bags of jelly beans contain $26$, $28$, and $30$ beans. The ratios of yellow beans to all beans in each of these bags are $50\%$, $25\%$, and $20\%$, respectively. All three bags of candy are dumped into one bowl. Which of the following is closest to the ratio of yellow jelly beans to all beans in the bowl?