Dividing by a fraction means multiplying by its reciprocal, then simplify.<br><br>
&bull; \( \frac{7}{10} \div \frac{5}{6} = \frac{7}{10} \times \frac{6}{5} = \frac{42}{50} \)<br>
&bull; Simplify: HCF of 42 and 50 is 2. \( \frac{42}{50} = \frac{21}{25} \)<br><br>
Final Answer: A = 21, B = 25