Formula: 10*9/2/ 1=45, with 45 methods.

Then there is only one way to take away all the defective products, and the probability is 1/45.

The method of taking all genuine products is to subtract 2 defective products, which is equal to 8 clothes, depending on how many ways to take them.

Formula: 8 * 7/2/1= 28,28 methods, then the probability is the genuine method divided by all methods, and the probability is 28/45.

The first positive method is to assume that it is 1 and 2 twice.

Then once and for all, all combinations of 1 of 2 and other 9 blocks are removed, and there are 8 combinations of 1 of 2 and other 9 blocks, and one * * * is 16. Because the combination is defective, it should be subtracted.

The probability is 16/45.

Answer:

I: 28/45

2: 1/45

Iii: 16/45

2. If X pieces of iron sheets are used as the box body and 190-X pieces of iron sheets are used as the box bottom, * * can get 8X boxes and 22( 190-X) box bottoms, and one box body and two box bottoms are made into a complete box, then only a batch of complete boxes are needed, that is, 2× 8x = 22×.