Neco 2022 Christian Religious Studies Question 7

Paul made three missionary journeys. Let the distance of the first journey be \(x\) km; the second journey covered twice that distance (\(2x\) km); the third journey covered the remaining distance, so the total distance is \(D = x + 2x + (D-3x)\). During the first journey he visited 5 cities, staying an average of 4 days per city; in the second journey he visited twice as many cities as the first, staying 2 days longer per city; in the third journey he visited three fewer cities than in the second, staying 1 day less per city than in the second. The total number of days Paul spent traveling (including days spent in cities) across all three journeys was 210 days. He travelled 40% of those travel days on road at an average speed of 30 km per day and the remaining 60% by sea at 15 km per day. Assuming all travel days are whole numbers, what was the total distance \(D\) (in kilometres) Paul travelled?