China Naming Network - Almanac query - The weather forecast accuracy of a weather station is 80.
The weather forecast accuracy of a weather station is 80.
(4/5)*(4/5)*(4/5)*( 1/5)*( 1/5)* C(5，2)= 128/725
Explain that the first accurate probability is 4/5, the second and third accurate probability is 4/5, the fourth and fifth inaccurate probability is 1/5, and then the third accurate and second inaccurate arrangement number is c (5,2) or c (5,3), so multiply this number.