To add 1/2 and 5/12, make both fractions have the same denominator:
1/2 is the same as 6/12, so 6/12+5/12=11/12
Thus, B is right.
Math. When no number occurs more than once in a data set, there is no mode. If each of two numbers occurs twice, we say the set is bimodal.
S=(n/2)(A+t)
x2 x2
2S=n(A+t)
--- --------
n n
2S n(A+t)
---=---------
n n
2S
---=A+t
n
.....2S
A=----- -t
......n
