At which time number of minutes elapsed since midnight is nine times the number of minutes before noon?
(a)8.30 a.m.
(b)6.56 a.m.
(c)9.46 a.m.
(d)10.48 a.m.
Answer
Answer (as printed): D
Explanation
Let the required time be $x$ minutes after midnight. Duration from 12 midnight to 12 noon $$\begin{aligned} & =12 \mathrm{hrs}=(12 \times 60) \mathrm{min}=720 \mathrm{min} . \\ & \text { So, } x=9(720-x) \Rightarrow 10 x=6480 \Rightarrow x=648 . \end{aligned}$$ Hence, required time $=648 \mathrm{min}$ after midnight = 10 hrs 48 min after midnight = 10.48 a.m.