Explanations:
First, work out the ratio of petrol to oil. In this question, it's 25:1. This means that for every 25 litres of petrol, you need 1 litre of oil.
Now, we need to find out how many litres of oil we need for 4 litres of petrol. To do this, we can use a simple proportion:
25:1 = 4:x
Where x is the number of litres of oil we need.
Cross-multiplying, we get:
25x = 4
Dividing both sides by 25, we get:
x = 4/25
Therefore, we need 4/25 litres of oil for 4 litres of petrol.
Finally, we need to convert this to millilitres. There are 1000 millilitres in a litre, so:
4/25 litres = 4/25 * 1000 = 160 millilitres
Therefore, we need 160 millilitres of oil for 4 litres of petrol at a ratio of twenty five to one.
