Can you please explain the concept of weighted average contribution margin and weighted average contribution margin ratio?

Can you please walk me through this problem?

Question 13 3 pts Speicher sells sports shoes and formal shoes. Sports shoes sell for $110 each and cost $50 in variable expenses to make. Formal shoes sell for $220 and cost $90 in variable expenses to make. Speicher's xed expenses are $50,000. If 39% of his revenues are from sports shoes, what is Speicher's weighted average contribution margin ratio? Provide your answer in decimal form (Le. 65.2% = 0.652} and to three decimal places. Do not round intermediary calculations.