Oscar makes purchases of an existing product (X) such that the marginal utility of the last unit he consumes is 10 utils and the price is $5. He also tries a new product (Y) and the marginal utility of the last unit he consumes is 8 utils and the price is $1. The equal marginal principle suggests that Oscar should

Increase his consumption of product Y and decrease his consumption of product X.

Explanation:

Oscar makes purchases of an existing product (X) such that the marginal utility of the last unit he consumes is 10 utils and the price is $5. He also tries a new product (Y) and the marginal utility of the last unit he consumes is 8 utils and the price is $1. The equal marginal principle suggests that Oscar should  increase his consumption of product Y and decrease his consumption of product X.

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