Probability Practice Test 1

The probability of selecting of 1 boy from the first groups is $\frac{1}{4}$ ,1 girls = $\frac{3}{4}$
The probability of 1 boy from the second is $\frac{1}{2}$ ,1 girls is $\frac{1}{2}$
The probability of selecting 1 boy from the third groups is $\frac{3}{4}$, 1 girl is $\frac{1}{4}$
The probability of selecting of 1 girl and 2 boys is
$=\frac{3}{4}\times \frac{1}{2}\times \frac{3}{4}$ $+\frac{1}{4}\times \frac{1}{2}\times \frac{3}{4}$ $+\frac{1}{4}\times \frac{1}{2}\times \frac{1}{4}$ $=\frac{13}{32}$