If m/n = 4/3 and r/t = 914 , then the value of 3mr - nt4nt - 7mr is = ?

Answer: Option B

$$\begin{array}{rl}& \frac{m}{n}\text{ = }\frac{4}{3}\text{ and }\frac{r}{t}\text{ = }\frac{9}{14}\\ & \Rightarrow \frac{mr}{nt}=\frac{4}{3}\times \frac{9}{14}\\ & =\frac{6}{7}\\ & \therefore \frac{3mr-nt}{4nt-7mr}\\ & =\frac{3\frac{mr}{nt}-1}{4-7\frac{mr}{nt}}\\ & =\frac{3\times \frac{6}{7}-1}{4-7\times \frac{6}{7}}\\ & =\frac{\frac{18}{7}-1}{4-6}\\ & =\frac{11}{7}\times \left(-\frac{1}{2}\right)\\ & =-\frac{11}{14}\end{array}$$