Question

The product of two rational numbers is 18/7 and one third of first number is -7/5 then half of the second number is ?

Answer 1

$$\begin{gathered} \mathrm{Let}x\mathrm{and}y\mathrm{be}\mathrm{the}\mathrm{first}\mathrm{and}\mathrm{second}\mathrm{rational}\mathrm{numbers}. \\ \mathrm{Now},\frac{x}{3}=-\frac{7}{5} \\ \Rightarrow x=-\frac{21}{5} \\ \mathrm{Now},x\times y=\frac{18}{7} \\ \Rightarrow -\frac{21}{5}\times y=\frac{18}{7} \\ \Rightarrow y=-\left(\frac{5\times 18}{21\times 7}\right)=-\frac{30}{49} \\ \mathrm{Now},\mathrm{half}\mathrm{of}\mathrm{second}\mathrm{number}=\frac{1}{2}\times \left(-\frac{30}{49}\right)=-\frac{15}{49} \end{gathered}$$