Решение:
\[ 1\frac{4}{7} = \frac{1 \times 7 + 4}{7} = \frac{7 + 4}{7} = \frac{11}{7} \]
\[ \frac{11}{7} \times 2 = \frac{11}{7} \times \frac{2}{1} = \frac{11 \times 2}{7 \times 1} = \frac{22}{7} \]
\[ \frac{22}{7} = 22 \div 7 = 3 \text{ (остаток } 1) = 3\frac{1}{7} \]
Ответ: 3&frac17;