Hi I have difficulty understanding the following exercise thank you for your help.

40. Refer to the above Figure. At a price of P1:

Select one:

1. D2 is more elastic than D1
2. D1 is more elastic than D
3. D2 is more elastic than D
4. D is more elastic than D1

46. What effect will an increase in the price of grapes have in the market for wine?

Select one:

1. Increase demand
2. Increase supply
3. Decrease supply
4. Decrease demand

47. Refer to data above. If the price falls to $4, then total revenue will:

Select one:

1. increase to $840
2. fall to $300
3. fall to $280
4. increase to $560

50. Refer to the following situation for the questions below. The coefficient of the price elasticity of demand for a good is 2. The price is now $5, and the quantity demanded at that price is 100. Refer to data above. If the price rises to $6, then total revenue will change to:

Select one:

1. $360
2. $500
3. $600
4. $300

53. If the cross-price elasticity of demand between A and B is 0.65, then we know that:

Select one:

1. A and B are complements
2. A and B are substitutes
3. the demand for B is inelastic
4. the demand for A is elastic

54. If the supply of apartments is increasing more rapidly than the demand, the likely result will be

Select one:

1. lower apartment rents.
2. higher apartment rents.
3. an increase in the demand for single-family homes, a substitute for apartments.
4. higher apartment rents and an increase in the demand for apartments and mobile homes.
5. an increase in the demand for mobile homes.

56. An increase in income from $7500 to $9000 causes an increase in purchase of a good from 3000 to 3500 units. The mid-point income elasticity of demand for that good must therefore be:

Select one:

1. 0.83
2. 0.61
3. 3.60
4. 1.20

59. A perfectly inelastic demand curve is likely to exist for which of the following items?

Select one:

1. fresh produce
2. beef
3. prescription drugs
4. beer