1. The outer diameter of bicycle tire is 0.7m If the wheel rotates 90 times per minute on average, how far can it go in 40 minutes? How many minutes does it take to cross a 567-meter bridge? (π=3. 14)

3.14 * 0.7 * 90 * 40 = 7912.8m.

40 minutes will do. 79 12.8 meters

567 ÷ (3.14 * 0.7 * 90) = 2.91min.

It takes 2.9 1 minute to cross a 567-meter bridge.

2. The circumference of the circular garden is 50.24m, and an area of 1/8 (one eighth) is reserved for planting chrysanthemums. How big is the area of chrysanthemum?

The circumference is 50.24 meters.

Radius =50.24/(2*3. 14)=8m.

Chrysanthemum covers an area of 3. 14 * 8? * 1/8 = 25 12m？

3. The diameter of the locomotive driving wheel of a train is1.5m. If the average speed is 300 revolutions per minute, how many kilometers does the train travel per hour?

3. 14 * 1.5 * 300 * 60 = 84780m = 84.78km

The speed of this train is 84.78 kilometers per hour.