Total number of fruits sold in a year = 10000 ⇒ Number of Watermelons sold in a year = 10000 × 17/100 = 1700 ⇒ Number of Watermelons sold in 6 months = 6 × 1700/12 = 850 ⇒ Number of Oranges sold in a year = 100000 × 10/100 = 1000 ⇒ Number of Oranges sold in a year = 100000 × 10/100 = 1000 ∴ Difference between number of Watermelons and oranges sold in 6 months = (850 - 500) = 350