Several types of petrol are produced during a petroleum refining process, and a last step combines them to obtain market products with specified quality measures.

Suppose $4$ different types of petrol are available, with values for the $2$ indexes of quality being $75$ and $149,96$ and $186,101$ and $183,$ and $103$ and $196,$ respectively.

Costs per litre of petroleum are $$0\mathrm{.}25,$ $$0\mathrm{.}85,$ $$0\mathrm{.}92,$ and $$0\mathrm{.}47$ respectively.

What is the minimal cost $($in pounds$)$ of a blend of petrols with a first quality index between $96$ and $101$ and a second index between $183$ and $186?$