In a frequency distribution, the mid-value of a class is 10 and width of each class is 6. The lower limit of the class is

(b) 7

Given:
Mid value of the class = 10
Width of each class = 6
Now,
Let the lower limit be x.
We know:
Upper limit = Lower limit + Class size

 = x + 6

Also,

Mid value $=\frac{x+x+6}{2}=\frac{2 x+6}{2}=x+3$

$\Rightarrow x+3=10$

$\Rightarrow x=7$

Thus, the lower limit is 7.