In a frequency distribution, the mid-value of a class is 12 and its width is 6. the lower
limit of the class is:
(a) 6 (b) 9 (c) 12 (d) 18

Mid value=6
∴6/2=3
∴to obtain the class,
3 must be subtracted from 12 to get lower limit,
& 3 must be added to 12 to get upper limit.
⇒lower limit=12-3
=9
∴answer in option"B"