Sure, let's find out the original cost of the meal.
Since a 10% tip was added to the original amount to get the total bill, we know that the total bill represents 110% of the original cost.
100% represents the full original price, and an extra 10% was added for the tip, giving a total of 110%.
The total bill you paid, £137.50, represents this 110%. Now, we want to find out what 100% (the original cost) is.
To find the original cost, we might set up the equation as follows:
(Total Bill / 110) * 100 = Original Cost
Following these calculations, we find that the original cost was approximately £125.