In Young's double slit experiment slit separation $\mathrm{d}=5\mathrm{\lambda }$. Then angular separation between 5th bright fringe and 2nd dark fringe (in radian) is 

Distance of 5th bright fringe from the centre of screen, ${\mathrm{y}}_5=5\mathrm{\lambda D}/\mathrm{d}$ and the distance of second dark fringe from the centre of the screen ${\mathrm{y}}_2=\left(1+\frac{\mathrm{d}}{2}\right)\mathrm{\lambda D}/\mathrm{d}=\frac{3\mathrm{\lambda D}}{2\mathrm{d}}$

$\therefore$ Angular separation $=\frac{{\mathrm{y}}_5-{\mathrm{y}}_2}{\mathrm{D}}=\frac{\frac{5\mathrm{\lambda D}}{\mathrm{d}}-\frac{3\mathrm{\lambda D}}{2\mathrm{d}}}{\mathrm{D}}=\frac{7\mathrm{\lambda }}{2\mathrm{d}}$

$=\frac{7\mathrm{\lambda }}{2\times 5\mathrm{\lambda }}=0.7\mathrm{radian}$