Passage Summary: People spend a much smaller portion of their paycheck on food now than they did thirty years ago. Since paychecks are bigger now, the author concludes that wages must be growing faster than food costs.

Conclusion: Incomes have increased at a faster rate than the price of food over the last thirty years.

Reasoning: The percentage of income that single people spend on food has dropped by half, and overall incomes have risen during that same period.

Analysis: This is a Sufficient Assumption question involving a mathematical relationship between three variables: income, food prices, and the percentage of income spent on food. The author observes that the percentage (Food Cost / Income) has decreased while Income has increased. However, this only proves food prices rose slower than income if we assume the *amount* of food being bought hasn't significantly decreased. Look for an answer that bridges this gap by ensuring that the quantity or quality of food consumed remained relatively stable, thereby guaranteeing the price-to-income ratio is the driving force.