The value of 51/3 ÷ 12/9 × 1/4 ( 10 + 31 - 1/5 ) = ?

Answer: Option A

$$\begin{array}{rl}& \text{According to question,}\\ & \text{5}\frac{1}{3}÷1\frac{2}{9}\times \frac{1}{4}\left(10+\frac{3}{1-\frac{1}{5}}\right)\\ & =\frac{16}{3}÷\frac{11}{9}\times \frac{1}{4}\left(10+\frac{3}{\frac{4}{5}}\right)\\ & =\frac{16}{3}÷\frac{11}{9}\times \frac{1}{4}\left(10+\frac{15}{4}\right)\\ & =\frac{16}{3}\times \frac{9}{11}\times \frac{1}{4}\times \frac{55}{4}\\ & =\frac{48}{11}\times \frac{1}{4}\times \frac{55}{4}\\ & =15\end{array}$$