Total number of Compartments = 7. Average number of passengers in eachcompartments = 15 total number of passenger in 7 compartment= 15 × 7 = 105. For the least number of passenger in 7th compartment,we have maximum number of passenger in first 6compartments. Maximum passenger in first compartment = 15. Maximum passenger in second compartment = 14. Maximum passenger in third compartment = 13. Maximum passenger in fourth compartment = 12 Maximum passenger in fifth compartment = 11. Maximum passenger in sixth compartment = 10. total number of passengers in 6 compartment = 75. ∴ Min. number of passenger in 7th compartment = 105 – 75 = 30.