#### Answer

a.) 9:91
b.) 91:9

#### Work Step by Step

a.) The odds in favor of E are found by taking the probability that E will occur
and dividing by the probability that E will not occur.
Odds in Favor = $\frac{P(E)}{P(not E)}$
We find the odds in favor of a child in a one-parent household having a parent who is a college graduate.
E: {9}
P(E) = $\frac{9}{100}$
P(not E) = 1 - P(E)
= 1 - $\frac{9}{100}$
=$\frac{100 - 9}{100}$ = $\frac{91}{100}$
Odds in Favor = $\frac{\frac{9}{100}}{\frac{91}{100}}$ = $\frac{9}{91}$
b.)The odds against E are found by taking the probability that E will not occur
and dividing by the probability that E will occur.
Odds against E = $\frac{P(not E)}{P(E)}$
Odds against E = $\frac{\frac{91}{100}}{\frac{9}{100}}$ = $\frac{91}{9}$
The odds against E can also be found by reversing the ratio representing the
odds in favor of E.