Xiao Ming and Xiao Hua ran 100 meters. When Xiaoming reached the finish line, Xiaohua was still 20 meters away. If Xiaoming retreats 20 meters when starting, who will be the first to reach the finish line? How many meters apart were they when they reached the finish line?

Solution: When Xiaoming ran 100 meters, Xiaohua ran (100-20 meters).

So the speed ratio of Xiaoming and Xiaohua is 100:80=5:4.

When Xiaoming runs120m, Xiaohua runs:120× 4/5 = 96m.

Distance to the finish line: 100-96 = 4m.

That is, when they reach the finish line, they are 4 meters apart.

Football usually consists of black and white leather blocks, with black leather blocks being regular pentagons and white leather blocks being regular hexagons. If there are 32 pieces of black and white leather on a ball, how many pieces are there?

Solution: 12 black pentagram.

White hexagon 20

Let the white leather be x, and the black leather be (32-X).

Let's look at white leather first. Black leather has three seams, so all the seams on a ball are 3X.

Let's look at black leather again. It has five seams with * * * * white leather, so all seams on a ball can also be expressed as 5×(32-X).

It can be concluded that:

3X=5×(32-X)

3X= 160-5X

8X= 160

X=20

32-X= 12

Known: 20 pieces of X white leather, 32-X black leather 12 pieces.