(1) x represents the number of apples bought, y represents the number of bananas.
(2) each term represents the total costs of a given fruit, so 0.50x is the total cost of apples and 0.30y is total cost of bananas.
(3) The coefficients are unit prices: coefficient 0.50 is the price of 1 apple, 0.30 is the price of 1 banana.