84 15 ——16 There is a vegetable plot of 800 square meters, with 2 / 5 tomatoes and the rest of cucumbers and eggplants. It is known that the planting area ratio of cucumbers and eggplants is 2:3. How many square meters are the planting areas of the three vegetables? Car a and car B start from the two places one after another. Car a runs 60 kilometers per hour, which is 1.2 times the speed of car B. car a meets car B at the midpoint of the two places six hours after departure. How many hours does car B start earlier than car a?

84 15 ——16 There is a vegetable plot of 800 square meters, with 2 / 5 tomatoes and the rest of cucumbers and eggplants. It is known that the planting area ratio of cucumbers and eggplants is 2:3. How many square meters are the planting areas of the three vegetables? Car a and car B start from the two places one after another. Car a runs 60 kilometers per hour, which is 1.2 times the speed of car B. car a meets car B at the midpoint of the two places six hours after departure. How many hours does car B start earlier than car a?

Planting tomato area: 800 times 2 / 5 = 320
Cucumber area: (800-320) times 2 / 5 = 192 or 800 times 800 times [(1-2 / 5) times 2 / 5] = 192
The area of eggplant: (800-320) multiplied by 3 / 5 = 288 or 800-320-192 = 288 is similar to the above method
Speed B: 60 divided by 1.2 = 50
Car B starts earlier than car a: 60 times 6 divided by 50 minus 6 = 1.2 hours