# A shipment of 10 microwaves contains 3 defective units. In how many ways can a vending company purchase 4 of these units and receive (a) all good units (b) two good units and (c) at least two good units?

##### 1 Answer

Jul 31, 2017

Out of 10 units of microwave there are 7 good units and 3 defective units.

(a)The number ways of receiving all 4 units perchased by the vending company to be good ones are

(b)The number ways of receiving 2 good units out of 4 units perchased by the vending company are

(c)The number ways of receiving at least 2 good units out of 4 units perchased by the vending company are