The film crew had a day's journey from city a to city B. they planned to walk 100 kilometers more in the morning than in the afternoon to have lunch in city C. due to the traffic jam, they arrived at a small town at noon and drove only one third of the original plan. After passing the town, the car drove 400 kilometers and stopped in the evening to have a rest. The driver said that one third of the journey from City C to here would reach the destination How many kilometers away?

The film crew had a day's journey from city a to city B. they planned to walk 100 kilometers more in the morning than in the afternoon to have lunch in city C. due to the traffic jam, they arrived at a small town at noon and drove only one third of the original plan. After passing the town, the car drove 400 kilometers and stopped in the evening to have a rest. The driver said that one third of the journey from City C to here would reach the destination How many kilometers away?

Suppose the distance between the two cities is x km, then we can know from the question: CA = 12x + 50 km, BC = 12x-50 km ∵ be = 13bc = 16x-503km, CE = 23bc = 13x-1003km, ad = 13ac = 13 (12x + 50) = 16x + 503de = ab-ad-be = x - (16x + 503) - (16x-503) = 23x, ∵ de = 400, ∵ 400 = 23x ∵ x = 600 (km), so the distance between the two cities is 600 km

To build an expressway, the original plan was to build 3600 meters per month and complete the task in 10 months. In fact, 900 meters per month was built. How many months have the task been completed?

Method 1: Total Quantity: 3600 x 10 = 36000 M
Actual working time: 36000 / 900 = 40 months
Method 2: the task was completed in x months
900X=3600X10
The solution is x = 40
So it takes 40 months
A: actually, the task was completed in 40 months

In order to further alleviate the traffic congestion, cities a and B decided to build a 90 km Coastal Expressway between the two cities. In order to complete the project two months ahead of schedule, the work efficiency of the original plan needs to be increased by 20%?

Suppose that the original plan is to repair x kilometers per month, then: (1 + 20%) · x · (90x − 2) = 90, the solution is: x = 7.5. After testing, x = 7.5 is the solution of the equation. Therefore, the original plan is to repair 7.5 kilometers per month