Minimum Medium Bags Sold

Let $a, b, c$ be the amounts spent by Ashish, Banti, Chintu. $a = b = c = V$. One buyer bought the large bag (cost Rs 1000), so each buyer spent $V \ge 1000$. Total spend $3V \ge 3000$. Known spend on small bags = $15 \times 50 = 750$. Known spend on large bag = $1000$. Total spend excluding medium bags = $1750$. Spend on medium bags = $200m$. Total revenue = $1750 + 200m = 3V \ge 3000$. $200m \ge 1250 \implies m \ge 6.25$. Check $m = 7$: Total revenue = $1750 + 1400 = 3150 = 3 \times 1050$. Each person spends Rs 1050. Possible distribution: Person 1: 1 Large (1000) + 1 Small (50) = 1050. Person 2: 7 Small (350) + 3 Medium (600) = 1050. Person 3: 7 Small (350) + 4 Medium (800) = 1050. Total: 1 Large, 15 Small, 7 Medium. Each spends 1050. Minimum $m = 7$.