A clock is set right at 5 a.m. The clock looses 16 minutes in 24 hours. What will be the correct time when the clock indicates 10 p.m. on the fourth day?
Step-by-step Solution:
The faulty clock loses 16 minutes every 24 hours. This means:
Let's convert the faulty time to hours:
$23 \text{ hours } 44 \text{ minutes } = 23 + \frac{44}{60} \text{ hours } = 23 + \frac{11}{15} \text{ hours } = \frac{356}{15} \text{ hours}$.
So, $\frac{356}{15}$ hours on the faulty clock corresponds to 24 hours on a correct clock.
The clock was set at 5 a.m. on the first day and it now shows 10 p.m. on the fourth day.
We need to find out how much correct time has passed when the faulty clock shows 89 hours.
Using the relationship from Step 1:
Correct Time = (Time on Faulty Clock) $\times \frac{\text{Correct Hours}}{\text{Faulty Hours}}$
Correct Time = $89 \times \frac{24}{\frac{356}{15}}$
Correct Time = $89 \times \frac{24 \times 15}{356}$
Since $356 = 4 \times 89$, we can simplify the expression:
Correct Time = $89 \times \frac{24 \times 15}{4 \times 89} = \frac{24 \times 15}{4} = 6 \times 15 = 90$ hours.
So, the actual duration that has passed is 90 hours.
We add the 90 hours of correct time to the starting time.
Adding 3 full days to 5 a.m. on Day 1 brings us to 5 a.m. on Day 4.
Now we add the remaining 18 hours:
5 a.m. (Day 4) + 18 hours = 23:00 hours = 11 p.m.
Therefore, the correct time is 11 p.m. on the fourth day.