I need help with part 2.

Part 1:

This week, Super-Save Supermarket lowered the price of apples from $1 to 90 cents per pound. The quantity of apples sold last week was 200 pounds. This week, the quantity sold was 250 pounds. Calculate the price elasticity of demand. Is itelastic,inelastic, orunitary elastic? What happens to total revenue?

Part 2:

Using the information given in the previous question, assume that last week Super-Save Supermarket sold 150 pounds of bananas and this week it sold 120 pounds of bananas. Are bananas and apples complements or substitutes? What is the cross elasticity of demand?