Question

The petrol rate is increased by Rs 5/- per litre .Now in rs 1320/- ,2 liters less petrol is obtained as compared to previous rate .Find the increased rate of petrol per litre.

Answer 1

Let the original price of petrol be Rs xAmount of petrol purchased = Rs 1740Number of litres purchased = (1740/x)Given that the price of petrol is increased by Rs 2 Therefore the number of litres of petrol purchased = [1740/(x + 2)]  ⇒ 3480 = x2 +2x ⇒  x2 + 2x – 3480 = 0 ⇒  x2 + 60x – 58x – 3480 = 0 ⇒  x(x + 60) – 58(x + 60) = 0 ⇒  (x + 60)(x – 58) = 0 ⇒  (x + 60)= 0 or (x – 58) = 0 ∴ x = –60 or x = 58 Since amount cannot be negative, x = 58 Thus the original price of petrol is Rs 58 per litre.