Registered because I have a (relatively simple - but not for me) maths problem and I can't work out how to calculate it.....

I basically put a load of unleaded in my car without thinking.... (it's a diesel car) and I'm trying to work out the percentage of petrol left in the tank after adding 4 top ups of diesel.

I've tried to calculate it in Excel but I've become confused (not hard for me).

Can anyone give me an answer and a simple formula for this problem? The details are below:

My tank was literally empty.

I put in 16.74 litres of petrol (before realising).

I then topped the tank up to full with 35.53 litres of diesel.

The car seemed sort of alright.... I then drove and kept topping up the tank to full with more diesel.

I drove and then put in a further

- 6.56 litres of diesel to full

- 8.30 litres of diesel to full

- 7.04 litres of diesel to full

- 18.51 litres of diesel to full

Assuming the petrol and diesel mixed perfectly (and was therefore used equally before each further topup of diesel) what percentage of petrol is still left in my tank?

If anyone can answer this I'd be most grateful.

Thanks in advance

PS Whats the likelyhood that my car is going to cost me a lot of money in the future :{