There is a plane that can fly in the air for up to four hours There is an aircraft that can fly in the air for up to 4 hours. Its speed when flying out and returning is 950km / h and 850km / h respectively. How many hours can this aircraft fly in the air at most? The question is how many kilometers

There is a plane that can fly in the air for up to four hours There is an aircraft that can fly in the air for up to 4 hours. Its speed when flying out and returning is 950km / h and 850km / h respectively. How many hours can this aircraft fly in the air at most? The question is how many kilometers

The ratio of flying out speed to flying back speed is: 950:850 = 19:17, so the ratio of flying out time to flying back time is: 17:19, the flying out time is: 4 × (17 ÷ (17 + 19)) = 9:17 (hours), the farthest flying distance is: 950 × 9:17 = 17:16150 (kilometers), about 1794 thousand

Cut a section of round steel into a biggest cone, the weight of the cut part is 8kg, and the weight of this section of round steel is ()
A. 24 kgB. 12 kgC. 16 kgD. 8 kg

8 △ 23 = 12 (kg), a: this round steel weighs 12 kg

When students of Dongcheng primary school go on a spring outing, if they rent 45 buses, the last one will only seat 30 people; if they rent 60 buses, they will just use two less buses. It is known that the rent of 45 buses is 240 yuan, and that of 60 buses is 320 yuan
Q: how many students are there in this school?
What's the cheapest way to rent a car?

If you want to rent a 45 seat bus, you need X-2 cars
Since the number of students is fixed, the equation is as follows
(x-1) * 45 + 30 = (X-2) * 60, x = 7
So there are 300 students: (7-2) * 60
It costs 7 * 240 = 1680 yuan to rent a 45 seat bus and 5 * 320 = 1600 yuan to rent a 60 seat bus
So it's cheapest to rent a 60 seat bus