Final answer:
Lwazi's indifference towards apples and oranges and constant MRS of 1 means he substitutes them at a one-to-one ratio, reflecting perfect substitutability in his consumption preferences. His indifference curves are straight lines and his consumption decisions will be based solely on the relative prices of these two goods.
Step-by-step explanation:
When Lwazi views apples and oranges as perfect substitutes, it implies that he has no preference between consuming an apple and an orange; one can be replaced by the other without any loss in the utility he derives from his consumption. The marginal rate of substitution (MRS) being equal to 1 indicates that Lwazi is willing to give up one apple for one orange, or vice versa, and still retain the same level of satisfaction. His indifference curves would be represented by straight lines with a slope of -1, demonstrating this constant trade-off rate.
Regarding the relation to prices in his indifference map, if the prices of apples and oranges are the same, Lwazi will be indifferent in his purchases. However, if one commodity were cheaper than the other, Lwazi would exclusively consume the cheaper good, as it would allow him to maximize his utility by getting the most for his money given that he views both goods as providing the same utility. This consumption pattern continues unless the relative prices change, prompting Lwazi to adjust his consumption in favor of the now cheaper good.