The Vale of $$\frac{17.35 + \frac{7}{5} of 55 - 7}{(42 \div 6 \times 8.35) - \frac{3}{7} of \left(\frac{2}{3} - \frac{1}{5}\right) + [291 \div (80 \div 8)]}$$ is:

$$\dfrac {17.35 +\dfrac {7}{5} of 55 - 7 } {( 42\div 6 \times 8.35 ) - \dfrac{3}{7}of \left(\dfrac {2}{3} - \dfrac{1}{5}\right)+ [291 \div (80 \div 8)]}$$

$$\Rightarrow \dfrac {17.35 +77 -7 } {(7\times 8.35) -\dfrac {3}{7} of \dfrac{10-3}{15} + 291 \div 10}$$

$$\Rightarrow  \dfrac { 17.35 +77 -7} {(58.45) -\dfrac {3}{7} \times \dfrac{7}{15} + 29.1}$$

$$\Rightarrow \dfrac { 94.35 -7} {(58.45)  + 29.1 -\dfrac {1}{5}}$$

$$\Rightarrow \dfrac { 87.35} {87.55 - 0.2}$$

$$\Rightarrow \dfrac { 87.35} {87.35 }$$

$$\Rightarrow 1  Ans $$