Four friends go out for a meal. they round the total amount including the service charge to the nearest whole pound and pay this amount to mando's. how much do they pay?

Let the rounded amount be A.
Each will pay therefore A/4, or 0.25A pounds.

Rounding decimals is very similar to rounding other numbers. if the hundredths and thousandths places of a decimal is forty-nine or less, they are dropped and the tenths place does not change. for example, rounding 0.843 to the nearest tenth would give 0.8. , your welcome !

Aand b is what i think