Question

Krishna lyer, a motorist uses 24% of his fuel in covering the first 20% of his total journey (in city driving conditions). If he knows that he has to cover another 25% of his total journey in city driving conditions, what should be the minimum percentage increase in the fuel efficiency for non-city driving over the city driving fuel efficiency, so that he is just able to cover his entire journey without having to refuel? (Approximately)

• A. 39.2%
• B. 43.5%
• C. 45.6%
• D. 41.2%

Answer 1

The correct option is B 43.5%

For 45% of the journey in city driving conditions, 54% of the fuel is consumed.
Hence, for the remaining 55% journey, 46% fuel is left.
Required increase in fuel effciency
$=\frac{\frac{55}{46}-\frac{45}{54}}{\frac{45}{54}}\times 100.$ = 43.5%