If a wheel has a radius of 0.3 meters, how many meters does it roll 1000 times

If a wheel has a radius of 0.3 meters, how many meters does it roll 1000 times

Advance 1884.9556m, 0.3x2 = 0.6m (diameter) 0.6x3.1415926 = 1.8849556m (perimeter) 1.8849556x1000 = 1884.9556m. 3.1415926 is pi, diameter multiplied by PI equals perimeter

The station stores a batch of goods, which can be transported in 8 hours by a large truck and 10 hours by a small truck. Now we are using two trucks at the same time
2.5 hours, just 36 tons. How many tons are there in total?
No words, equations, just formulas and answers
I'll finish it in two days

2.5 hours, 2.5x (1 / 8 + 1 / 10) = 2.5x (5 / 40 + 4 / 40) = 5 / 2x9 / 40 = 9 / 16
36 △ 9 / 16 = 64 tons
A: a total of 64 tons

There is a batch of goods in the station, which can be transported in 15 hours by large trucks, 30 hours by medium trucks, 45 hours by small trucks, and how many hours by three trucks at the same time?
45/7
90/7
45/11
90/11

Let the total amount of work be unit "1". So the work efficiency of a is 1 / 15, B is 1 / 30, C is 1 / 45. If it is transported together, then the work efficiency is 1 / 15 + 1 / 30 + 1 / 45 = 11 / 90. So the work time is 1 / (1 / 15 + 1 / 30 + 1 / 45) = 90 / 11

Transport 62 tons of rice from land a to land B. Transport 10 tons of rice by large truck and 95 yuan by small truck
Please design a plan that costs the least

Scheme: 5 big cars and 3 small cars;