Ans 1.

​According to the law of equi-marginal utility, a rational individual does not spend his Marginal Utility entire income on one commodity. Consumer knows that if he purchases more units of the same commodity then marginal utility of each successive unit would decline. Hence, to get the maximum utility from his limited income, he spends his limited income in such a way that the last unit of money spent on different commodities yields equal marginal utility.

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