Answer:
[tex]\huge\boxed{\sf 2\frac{5}{7} \ hours}[/tex]
Step-by-step explanation:
Time taken to mix the cake = [tex]\displaystyle \frac{3}{7} \ hours[/tex]
Time taken to bake it = [tex]\displaystyle 2 \frac{2}{7} \ hours[/tex]
Time taken altogether:
[tex]\displaystyle = \frac{3}{7} + 2\frac{2}{7} \\\\= \frac{3}{7} + \frac{7 \times 2+2}{7} \\\\= \frac{3}{7} + \frac{16}{7} \\\\= \frac{3+16}{7} \\\\=\frac{19}{7} \\\\= 2\frac{5}{7} \ hours\\\\\rule[225]{225}{2}[/tex]
