Single-cow consumption time from group usage: In a dairy farm, 40 cows eat 40 bags of husk in 40 days at a steady rate. Based on this information, in how many days will one cow consume exactly one bag of husk?

Introduction / Context:
This is the same structure as a standard work-and-consumption problem. We reframe group consumption (many cows over many days) as a per-cow-per-day rate and then invert it to find days for a single cow to finish a single bag.

Given Data / Assumptions:

• Cows = 40
• Bags = 40
• Days = 40
• Rate per cow per day is constant.

Concept / Approach:
Compute bags consumed per cow per day: bags / (cows * days). Then, the required days for 1 cow to finish 1 bag is the reciprocal of that per-cow-per-day rate.

Step-by-Step Solution:
Cow-days = 40 * 40 = 1600Bags per cow-day = 40 / 1600 = 1/40Days for 1 bag by 1 cow = 1 / (1/40) = 40 days

Verification / Alternative check:
Cross-check: If one cow takes 40 days for a bag, 40 cows take 40 days for 40 bags—identical to the original statement, confirming consistency.

Why Other Options Are Wrong:
1 day is unrealistic at the given rate; 32 and 28 are too fast; 76 is too slow and inconsistent with the provided totals.

Common Pitfalls:
Mixing up “per day per cow” with “per day for the herd,” which leads to incorrect reciprocals and wrong answers.

Final Answer:
40