Total items = 126. Cakes : Muffins = 2 : 7.<br><br>
[[model:questions/solutions/q10496.png]]<br><br>
Total units = 2 + 7 = 9 units<br>
&bull; 9 units → 126<br>
&bull; 1 unit → 126 ÷ 9 = 14<br>
&bull; Cakes = 2 units = 2 × 14 = 28<br>
&bull; Muffins = 7 units = 7 × 14 = 98<br><br>
Now split each group:<br>
Cakes &mdash; chocolate : vanilla = 1 : 1, so chocolate cakes = \( \frac{1}{2} \) × 28 = 14<br>
Muffins &mdash; chocolate : vanilla = 4 : 3, total 7 parts, so chocolate muffins = \( \frac{4}{7} \) × 98 = 56<br><br>
Total chocolate items = 14 + 56 = 70<br>
Check: Vanilla cakes = 14, vanilla muffins = \( \frac{3}{7} \) × 98 = 42. 14 + 56 + 14 + 42 = 126. ✓<br><br>
Final Answer: 70