(,,frac{7}{{19}}:frac{2}{3} + frac{{12}}{{19}}:frac{2}{3})
Giải chi tiết:
(begin{array}{l},,frac{7}{{19}}:frac{2}{3} + frac{{12}}{{19}}:frac{2}{3}\ = left( {frac{7}{{19}} + frac{{12}}{{19}}} right):frac{2}{3}\ = ,,,,,,,frac{{19}}{{19}}:frac{2}{3}\ = 1:frac{2}{3}\ = frac{3}{2}end{array})
Chọn B