Đáp án: `353/175`
Giải thích các bước giải:
\(\dfrac{3}{5} :\dfrac{ 5}{6}: \dfrac{ 6}{7} :\dfrac{ 7}{8} + \dfrac{2}{5} + \dfrac{23}{35}\)
\(=\dfrac{3}{5}\times\dfrac{6}{5}\times\dfrac{7}{6}\times\dfrac{8}{7} + \dfrac{2}{5} + \dfrac{23}{35}\)
\(=\dfrac{3\times8}{5\times5} + \dfrac{2}{5} + \dfrac{23}{35}\)
\(=\dfrac{24}{25} + \dfrac{2}{5} + \dfrac{23}{35}\)
\(=\dfrac{1}{5}(\dfrac{24}{5} + 2 + \dfrac{23}{7})\)
\(=\dfrac{1}{5}(\dfrac{24\times7+2\times35+23\times5}{35})\)
\(=\dfrac{1}{5}\times\dfrac{353}{35}\)
\(=\dfrac{353}{175}\).
