Question

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 1

The correct option is D $10:48$ a.m.

Let the required time be $x$ minutes after midnight.
Duration from $12$ midnight to $12$ noon
$=12$ hrs. $=12\times 60$ min. $=720$ min.
So, $x=9(720-x)$
$\Rightarrow 10x=9\times 720$
$\Rightarrow x=648$ min.
Hence, required time
$=648$ min. after midnight
$=10$ hrs. $48$ min. after midnight
$=10:48$ a.m.