Answer
(a) $\frac{1}{4}$
(b) $\frac{29}{12}$ or $2\frac{5}{12}$
Work Step by Step
Part (a)
Step 1: $\frac{3}{4}\times\frac{7}{21}$
Step 2: $\frac{3}{4}\times\frac{1}{3}$
Step 3: $\frac{1}{4}\times\frac{1}{1}$
Step 4: $\frac{1}{4}$
Part (b)
Step 1: $\frac{1}{2}\times4\frac{5}{6}$
Step 2: $\frac{1}{2}\times\frac{29}{6}$
Step 3: $\frac{29}{12}$ or $2\frac{5}{12}$