7pBegin by converting ml to litres: 100ml = 0.1l1l = 70 p.1l = xTo solve for x, cross multiply then divide.70p * .1 litre / 1 litre = 7p(While it would be faster to divide by ten upon recognizing thepattern, always cross multiply because the numbers will not alwaysperfectly work out, especially when decimals are involved)