Given: Richard's car runs 25 km in one litre of petrol Petrol costs Rs. 75/litre Richard spends Rs.1500 on petrol Concept Used: Concept of Unitary Method. In this concept we will first calculate the value of a single unit then we will calculate our desire value by multiplying the single unit value Total distance travel = Distance travel/fuel consumed × Total fuel Calculation: Total money spend = Rs. 1500 Price of petrol = Rs. 75/liter He can buy total 1500/75 = 20 litre petrol on that money Now, in 1 litre petrol car runs 25 km ∴ In 20 liter petrol car runs = 20 × 25 = 500 km ∴ Richard’s car can go 500 km on Rs. 1500 of petrol