Question

A mechanical clock is at present showing $4$ hours $40$ minutes $6$ seconds. Assuming that it loses $6$ seconds in every hour, what time will it show after exactly $3\frac{1}{2}$ hours?

• A. $8$ hours $10$ minutes $27$ seconds
• B. $8$ hours $10$ minutes $6$ seconds
• C. $8$ hours $9$ minutes $45$ seconds
• D. $8$ hours $9$ minutes $34$ seconds

Answer 1

The correct option is C $8$ hours $9$ minutes $45$ seconds

Time lost in $3\frac{1}{2}$ hours $=3\frac{1}{2}\times 6=21$ seconds.
Correct time after $3\frac{1}{2}$ hours
$=$ $4$ hours $40$ minutes $6$ seconds $+$ $3$ hours $30$ minutes
$=8$ hours $10$ minutes $6$ seconds.
Time shown by the clock
$=8$ hours $10$ minutes $6$ seconds $-21$ seconds
$=8$ hours $9$ minutes $45$ seconds