Question

A motorist uses 24% of his fuel in covering the first 20% of his total journey (in city driving conditions). He has to cover another 25% of his total journey in city driving conditions. What should be the minimum

Answer 1

Answer:

43.48 % fuel efficiency increase required

Step-by-step explanation:

Complete Question :

What should be the minimum percentage increase in fuel efficiency for non-city driving over that in city driving, so that he is just able to cover his entire journey without having to refuel

A motorist uses 24% of his fuel in covering the first 20% of his total journey (in city driving conditions).

Let say Total Journey = D km

Total Fuel = F  

=> 0.24F  Consumed in 0.2D km city condition

=> Fuel consumed in 25% of Citu condition =  (24/20) * 25  = 30%

=> 0.3F Consumed in 0.25D  km city condition

City Condition total Journey = 0.2D + 0.25D = 0.45D

City Condition fuel consumption = 0.24F + 0.3F = 0.54F

Fule Efficiency  = 0.45D/0.54F   =  5D/6F

Remaining Journey = D -0.45D  = 0.55D

Remaining Fuel = F - 0.54F = 0.46F

Fuel Efficiency = 0.55D/0.46F   = 55D/46F

increase in fuel efficiency = 55D/46F  -  5D/6F

= (165D - 115D)/138F

= 50D/138F

% increase in efficiency =  100 * (50D/138F) /(5D/6F)  

= 100 * 300 / 690

= 43.48 %

43.48 % fuel efficiency increase required