Question

In a mixture of 100 liters of fuel, the ratio of petrol and adulterated particles is 4:1. If pump owner wants to the ratio to be 19:1, by what proportion should the adulterated particles be reduced?

Answer 1

4x + x = 100

5x =100
x = 20

petrol = 80
adulterated = 20

now owner wants = 19x + x = 100
20x = 100
x = 5

so petroleum = 95
adulterated = 5

so 20 - 20x = 5
20x = 15
x= 3/4