Mixture 'A' has only petrol and diesel in the ratio 5:4

Solution

Let the quantity of final mixture be 315 units (L.C.M. of 9, 5 and 7) So, quantity of mixture 'A' in the final mixture = 315 X (3/7) = 135 units Quantity of mixture 'B' in the final mixture = 315 - 135 = 180 units Quantity of petrol in 135 units of mixture 'A' = 135 X (5/9) = 75 units Quantity of diesel in 135 units of mixture 'A' = 135 - 75 = 60 units Quantity of petrol in 180 units of mixture 'B' = 180 X (3/5) = 108 units Quantity of diesel in 180 units of mixture 'B' = 180 - 108 = 72 units So, quantity of petrol in the final mixture = 75 + 108 = 183 units Quantity of diesel in the final mixture = 60 + 72 = 132 units Therefore, required ratio = 183:132 = 61:44