A historian studying ancient astronomy translates 240 astronomical records. If 25% are incomplete, 2/5 of the complete records document planetary motion, and each planetary document contains 32 observations, how many observations are documented?

Tue, 05 May 2026 08:41:30 +0000

Title: Unlocking the Stars: How a Historian Deciphers Ancient Astronomy Through 240 Astronomical Records A historian dedicated to unraveling the mysteries of ancient astronomy recently completed a groundbreaking effort: translating 240 original astronomical records from long-lost manuscripts. This monumental achievement not only preserves a vital piece of human knowledge but also reveals profound insights into how early civilizations understood the cosmos. Out of the 240 records, 25% were found to be incomplete due to damage or fragmentation. This means 25% of 240—240 × 0.25 = 60 records are missing key information. Subtracting the incomplete entries gives 240 – 60 = 180 complete astronomical records available for detailed study. Of these 180 complete documents, the historian discovered that 2/5 specifically document planetary motion—highlighting the advanced observational and record-keeping skills of ancient astronomers. Calculating the number of planetary motion records:
(2/5) × 180 = 72 records describe planetary movements.