A retail company operates two stores, Store A and Store B. The company provides the following information for the month of January:

Store A:

• Sales revenue: $50,000
• Variable costs: $20,000
• Fixed costs: $10,000

Store B:

• Sales revenue: $80,000
• Variable costs: $30,000
• Fixed costs: $15,000

Calculate the following:

a) The contribution margin for each store for the month of January.

b) The weighted average contribution margin for the company for the month of January.