## Trending News

# 離散數學問題????需要幫忙解答

1.Find the number of 13-card bridge hands selected from an ordinary

52-card deck. How many bridge hands contain all four aces?

2.A shipment of 50 microprocessors of which 4 are defective. In how

many ways can we select a set of 4 non-defective microprocessors?

4. What is the coefficient of x^7 in (1+x)^11 ?

請各位大大幫忙解答~~~~謝謝

### 2 Answers

- 1 decade agoFavorite Answer
1.Find the number of 13-card bridge hands selected from an ordinary

52-card deck. How many bridge hands contain all four aces?

從52章樸克牌組中選出13張，有多少種有全部四張A

52－4＝48，扣除4張A，還有48張，

13－4＝9，從剩下的48張選出9張的組合，

所以有48×47×46×45÷4÷3÷2＝194580種

2. A shipment of 50 microprocessors of which 4 are defective. In how

many ways can we select a set of 4 non-defective microprocessors?

50個處理器中有四個是壞的，挑出一組四個不是壞的，有幾種方式？

50－4＝46

從剩下的46個選出4個的組合，

所以有46×45×44×43÷4÷3÷2＝163185種

4. What is the coefficient of x^7 in (1+x)^11 ?

在（1＋x）的十一次方中，x七次方的係數

也就是從11組（1＋x）中取7組為x的組合

所以有11×10×9×8×7×6×5÷7！＝330