To obtain the greatest satisfaction from a fixed level of expenditure on two goods, X and Y, a consumer should divide spending between the two goods so that
- Amarginal utility of X = price of X and marginal utility of Y = price of Y
- Bmarginal utility of X plus marginal utility of Y is maximised
- Cmarginal utility of X = marginal utility of Y
- Dmarginal utility of X / price of X = marginal utility of Y / price of Y