Distance between A & B = 35*2 + 45* 2 =160 km
Distance covered by Aditi in each speed segment = $\frac{160}{3}$
petrol consumed by Aditi when he drives at 30kmph= $\frac{160}{3}*\frac{1}{16}$
petrol consumed by Aditi when he drives at 40kmph= $\frac{160}{3}*\frac{1}{24}$
petrol consumed by Aditi when he drives at 50kmph=$\frac{160}{3}*\frac{1}{16}$
The quantity of petrol consumed by Aditi for the journey is=
$\frac{160}{3}*\frac{1}{16}$ +$\frac{160}{3}*\frac{1}{24}$ +$\frac{160}{3}*\frac{1}{16}$ =8.91
Hence,Option(C)8.91 .