louella's evaluation of the cost of a new car, how many miles per gallon it gets, and whether there is enough room for her growing family represents her motives; how the car makes her feel when she's driving it and whether she thinks her friends will be impressed when they see her behind the wheel reflect her motives.

Louella's evaluation of the cost   for her growing family represents her RATIONAL motives; how the car makes her feel when she is driving it behind the wheel reflected her EMOTIONAL motives.
1. Rational motives refers to decision making that are based on completely objective criteria. For instance, when a consumer want to purchase a product,he has to base his decision on some criteria such as the price of the product, its utility, profits that will be derived from it, etc. 
2. Emotional motive on the other hand based decisions to buy products on personal or subjective criteria such as love for the product, vanity, pride, entertainment, envy, etc. Emotional motive originates from psychological needs or impulse rather than from carefully thought out plans.