Little genius grade six volume one monthly mathematics examination paper 2 A freight car from port a to port B travels 65 kilometers per hour and arrives in 5 / 4 hours. It takes 3 / 5 hours to return from the original road. How many kilometers per hour does the freighter travel on average?

Little genius grade six volume one monthly mathematics examination paper 2 A freight car from port a to port B travels 65 kilometers per hour and arrives in 5 / 4 hours. It takes 3 / 5 hours to return from the original road. How many kilometers per hour does the freighter travel on average?

This is a problem of distance, as long as you always remember that speed = distance △ time, distance = time × speed. If the distance to go is the same as that to return, then take the distance to go = speed to go × time to go, that is s = 65 × 5 / 4, the speed to return = distance △ time to return = s △ 3 / 5 = 65 × 5 / 4 △ 3 / 5, and calculate the final result by yourself

Using 800 tons of ore to make iron, 520 tons of slag can be produced. What is the iron content of this kind of ore______________
The science and technology team used 400 corn seeds to carry out germination test, and 10 of them did not germinate. The germination rate was calculated

35% 39 / 40

Grade 6 Volume 1 mathematics 37 pages per lesson
Class 6 (1) did the experiment in groups. Each student had a beaker with 200g water, a measuring cylinder, a balance, an empty cup and 24g salt on his desk. The teacher asked the students to prepare a cup of salt water according to the ratio of water and salt 20:3. If you were doing the experiment, how would you prepare the cup of salt water? How many kilograms of salt water would you prepare?

Use 24 / 3 = amount of salt water
The prepared brine weighs 8 kg
Water 200 / 20 = the amount of water
The prepared water weighs 10 kg
=10：3