The school bought five pairs of table tennis boards in the shop and handed them over to 120 yuan. The recovered money can also be used to buy five ping-pong balls from 2 yuan. What's the price of each pair of table tennis?

( 120-5*2)/5=22

Xiaoya walked 600 meters from home to the Children's Palace in five minutes. At this speed, it takes 15 minutes to reach the Children's Palace. How far is Xiaoya's home from the Children's Palace?

Xiaoya's home is ***5+ 15=20 minutes away from the Children's Palace, and the standard problem solving is 600/5*20=2400 meters.

Clever solution: walk 600 meters in 5 minutes ***20 minutes, and use 20/5*600=2400 meters directly.

I read a book carefully. I planned to read 24 pages a day, 18 days. Actually I read 12 pages a day. How many days did I study?

24* 18/(24+ 12)= 12

Think: A, B and C, the average of A and B is 16.4, the average of A and C is 20.2, and the average of B and C is 2 1. What are the numbers of a, b and c?

A+B = 16.4 * 2 = 32.8 A+C = 20.2 * 2 = 40.4 B+C = 2 1 * 2 = 42。

After the three formulas are added and divided by 2, A+B+C =57.6. Subtract the above three formulas with this formula to get the result.

A = 15.6，B = 17.2，C =24.8。