An agricultural innovator models crop yield improvements: a sequence of five annual yields forms an arithmetic progression. The sum of the first and third years is 120 tons, and the fifth year’s yield is 50 tons more than the second. Find the first year’s yield.

In an era when global food security and sustainable farming practices dominate agricultural conversations, one innovation is quietly reshaping how yields are tracked and optimized: the arithmetic progression model. As farmers and agri-tech innovators seek precise, predictable patterns in crop performance over time, understanding the underlying math enables smarter forecasting and resource planning. This model offers a structured way to analyze annual yield trends—revealing insights hidden within data, especially in regions where consistent production drives economic resilience. Understanding how five-year yield sequences unfold mathematically opens doors to more effective yield management.

This sequence follows a clear mathematical pattern: each annual increase (or decrease) remains constant between successive years. This structure simplifies forecasting—allowing early identification of trends that could impact planting decisions, supply chain logistics, or investment strategies. For those in U.S. agriculture, particularly in key yield regions, such analytical tools are no longer optional, but increasingly essential.

Understanding the Context

The question at the center isn’t just mathematical—it reflects real-world pressures and progress:
The sum of the first and third yields over five years is exactly 120 tons, and the fifth year’s yield exceeds the second year’s by 50 tons. These two clues form the foundation for solving the sequence, offering clarity where crop data might otherwise seem inconsistent.

The arithmetic progression consists of five terms, labeled by year: Year 1, Year 2, Year 3, Year 4, Year 5. Let the first yield be a, and the common difference be d. Then the yields are:
a, a + d, a + 2d, a + 3d, a + 4d

Using the first condition—sum of the first and third yields:
a + (a + 2d) = 120 → 2a + 2d = 120 → a + d = 60 (H1)

The second condition states the fifth year’s yield exceeds the second by 50 tons:
(a + 4d) – (a + d) = 50 → 3d = 50 → d = 50/3 ≈ 16.67 (H2)

Key Insights

Substitute d = 50/3 into (a + d) =