Đáp án đúng: B
Giải chi tiết:\(\begin{array}{l}\,\left( {\frac{1}{2} + \frac{4}{5}} \right) \times \frac{2}{3} = \frac{1}{2} \times \frac{2}{3} + \frac{4}{5} \times \frac{2}{3}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,\,\,\,\,\frac{1}{3}\,\,\,\, + \,\,\,\,\,\frac{8}{{15}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,\,\,\,\,\frac{5}{{15}} + \frac{8}{{15}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,\,\,\,\,\,\,\frac{{13}}{{15}}\end{array}\)
Chọn B