Answer
$P(rejected)=\frac{1,054,325}{8,214,570}\approx0.1283$
Work Step by Step
Combinations of 120 distinct electronic components (defective or not) taken 4 at a time (the order in which the components are selected does not matter):
$N(S)=~_{120}C_4=\frac{120!}{4!(120-4)!}=\frac{120!}{4!\times116!}$
But, $120!=120\times119\times118\times117\times(116\times115\times114\times...\times3\times2\times1)=120\times119\times118\times117\times116!$
$_{120}C_4=\frac{120\times119\times118\times117\times116!}{4!\times116!}=\frac{120\times119\times118\times117}{4\times3\times2\times1}=8,214,570$
There are $120-4=116$ non defective components.
Combinations of 116 distinct non defective electronic components taken 4 at a time (the order in which the components are selected does not matter):
$N(non~defective)=~_{116}C_4=\frac{116!}{4!(116-4)!}=\frac{116!}{4!\times112!}$
But, $116!=116\times115\times114\times113\times(112\times111\times110\times...\times3\times2\times1)=116\times115\times114\times113\times112!$
$_{116}C_4=\frac{116\times115\times114\times113\times112!}{4!\times112!}=\frac{116\times115\times114\times113}{4\times3\times2\times1}=7,160,245$
Using the Classical Method (page 259):
$P(accepted)=\frac{N(non~defective)}{N(S)}=\frac{7,160,245}{8,214,570}\approx0.8717$
The event "rejected" is the complement of "accepted".
Using the Complement Rule (page 275):
$P(rejected)=1-P(accepted)=1-\frac{7,160,245}{8,214,570}=\frac{8,214,570}{8,214,570}-\frac{7,160,245}{8,214,570}=\frac{1,054,325}{8,214,570}\approx0.1283$
