The ages (in years) of 150 people attending a health camp, grouped in unequal classes:
0-5 -> 18, 5-15 -> 32, 15-35 -> 45, 35-60 -> 37, 60-90 -> 18.
Which class contains the median, and what class size h goes with it?

Cumulative: 18, 50, 95, 132, 150, so $n=150$ and $\frac{n}{2}=75$. The first cf to reach 75 is 95, so the median lies in 15-35, whose own width is $35-15=20$. 5-15 is the row that supplies cf = 50, not the median class. 35-60 is one row too far. The last option keeps the right class but borrows $h=10$ from the second class — $h$ must always be the median class's own width, especially when the widths are unequal.