Football is made of black and white leather, black leather is 5-Sided, white leather is 6-sided. A football Black Leather 12, then white leather? It has a picture A piece of white skin has only three sides connected with black skin. The other three are white.

Football is made of black and white leather, black leather is 5-Sided, white leather is 6-sided. A football Black Leather 12, then white leather? It has a picture A piece of white skin has only three sides connected with black skin. The other three are white.

Black and white have the same number of edges, 5 * 12 = 60
60/6=10

For a person over 100 years old, he was a year old in a * a, so how old was he in 2001

a+(2001-a*a)

Who will teach me? Before [1 / 05 / 2009], please
1. Party A and Party B travel from two places 18 kilometers away from each other at the same time. Party A travels 4 kilometers per hour, and Party B travels 5 kilometers per hour. If Party C starts from the same direction with Party A by motorcycle at the same time, he travels 45 kilometers per hour. After meeting Party B, he immediately turns around and drives to Party A. in this way, he keeps going back and forth until Party A and Party B meet. How many kilometers has Party C traveled?
2. It takes 24 seconds for a train to pass through the first tunnel with a length of 360 meters, and then it takes 16 seconds to pass through the second tunnel with a length of 216 meters?
3. There are two islands a and B in the lake. Both a and B have to swim back and forth between the two islands. They start from a and B at the same time. When they first meet, they are 700 meters away from a island and 400 meters away from B island. Q: how far is the distance between the two islands?
4. The distance between a and B is 486 km. A slow train starts from a and runs 52 km per hour. At the same time, a fast train starts from B and runs 70 km per hour. The two trains are running in the same direction. The slow train is in front of the fast train. How many hours can the fast train catch up with the slow train?

It seems very complicated, but it's very simple. To find the distance is the speed multiplied by the time speed. The known time is actually the time when Party A and Party B meet each other. 18 / (4 + 5) = 2, so the problem of distance = 2 * 45 = 902 is more difficult than the previous one. First, to find the speed of the car = (360-216) / (24-16) = 18