A bakery opened with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon and 60\% of the remaining rolls were sold between noon and closing time. How many dozen rolls were left unsold?
(a)6
(b)8
(c)10
(d)12
Answer
Answer (as printed): B
Explanation
Number of rolls sold by noon $=\frac{1}{2}$ of 40 dozen $=20$ dozen. Number of rolls sold between noon and closing time $$=60 \% \text { of } 20 \text { dozen }=\left(\frac{60}{100} \times 20\right) \text { dozen }=12 \text { dozen. }$$ Number of rolls left unsold $=[40-(20+12)]$ dozen $=8$ dozen.
Explanation as extracted from the printed page; notation may be imperfect.