Measurements are grouped as 10.1–10.5, 10.6–11.0, 11.1–11.5. After the classes are made continuous, the upper boundary of the first class is ____.

**Modal class**: class with HIGHEST frequency.

**Mode formula**:
**Mode = $l+h\times (f$₁ − $f$₀) / $(2f$₁ − $f$₀ − $f$₂)**

Where:
- $l$ = lower limit of modal class
- $h$ = class width
- $f$₁ = frequency of modal class
- $f$₀ = frequency of class BEFORE modal class
- $f$₂ = frequency of class AFTER modal class

**Example**: Modal class 30–40 with $f$₁ = 12, $f$₀ = 5, $f$₂ = 8. $l=30,h=10$.
Mode = $30+10\times (12-5)/(24-5-8)=30+\frac{70}{11}$ ≈ 36.36.