Arrange the number a = 710, b = 5/8, c = 2/3 in descending order = ?

Answer: Option B

$$\begin{array}{rl}& a=\frac{7\times 24}{10\times 24}=\frac{168}{240}\\ & b=\frac{5\times 30}{8\times 30}=\frac{150}{240}\\ & c=\frac{2\times 80}{3\times 80}=\frac{160}{240}\\ & \text{The descending order}\\ & \text{ = }a>c>b\end{array}$$