1: Faye Wong borrows books from the mountain library. He goes up the mountain 3 kilometers per hour and returns 6 kilometers per hour. Ask him for the average speed of going up and down the mountain. Explain the process in detail and explain the meaning of each formula. Thank you)

Let the length of mountain road be 1.

The climbing time is 1÷3= 1/3 hours.

Downhill time is 1÷6= 1/6 hours.

So the total * * * time is1/3+1/6 =1/2 hours.

The average speed is 1× 2 ÷ 1/2 = 4km/h (distance divided by time = speed).

2. The bus and the train run in opposite directions from the midpoint between Party A and Party B at the same time. Five hours later, the bus arrives at Party A, and the truck is 60 kilometers away from Party B. Given that the speed ratio of the truck to the bus is 5:7, how many kilometers are there from Party A and Party B? What does the speed ratio of 5:7 mean? Explain the meaning of each formula. Thank you. )

The speed ratio of 60/5 * 7 * 2 = 168(km)5:7 is that at the same time, the bus runs 5 and the train runs 7, so part of the speed ratio calculated by 60/5 is 12, multiplied by the number of times the train runs 7, which is the distance the train runs. Because the train runs from the end, it has to be multiplied by 2.

3. Party A and Party B completed 242 machine parts at the same time. It takes six minutes for Party A to make a part and five minutes for Party B to make a part. How many parts did Party A and Party B make when they finished this batch of parts? Explain the meaning of each formula, thank you. )

Let a be x.

B manufacturing (242-X)

Two people use the same time, so: 6X=5(242-X) Two people start and stop at the same time, so the time is the same.

X= 1 10。

So A did 1 10, and already did 132.

There is a batch of goods in the warehouse, and the weight ratio of the transported goods to the remaining goods is 2:7. If 64 tons are transported, the remaining goods are only one-ninth of the original goods in the warehouse. How many tons are there in the warehouse? What does the weight ratio of 2:7 mean? Explain the meaning of each formula. Thank you. )

The weight ratio is 2:7, that is, there are 9 pieces of goods in the warehouse, 2/9 of which have been transported away, leaving 7/9.

Only one-ninth of the 64 tons are left after being transported, so the 64 tons transported account for 7- 1/9 = 6/9. Divide 64 by 6/9 to get 96 tons.