For the following distribution:

Class	0-5	5-10	10-15	15-20	20-25
Frequency	10	15	12	20	9

The sum of the lower limits of the median class and the modal class is
(a) 15
(b) 25
(c) 30
(d) 35

(b) 25

Class	Frequency	Cumulative frequency
0-5	10	10
5-10	15	25
10-15	12	37
15-20	20	57
20-25	9	63

Now, N=63
$\therefore \frac{N}{2}=32.5$
The cumulative frequency just greater than 32.5 is 37 and the corresponding class is 10-15.
$\therefore \mathrm{Median}\mathrm{class}=10-15$
Here, the highest frequency is 20 and its corresponding class is 15-20.
$\therefore \mathrm{Modal}\mathrm{Class}=15-20$
Sum of the lower limits of the median class and modal class = 10 + 15 = 25