A clock is set right at 10 am.The clock gains 10minutes in 24 hours. what will be the true time when the clock indicate 3PM of the following day?

Question

A news paper 

Answer 1

At 10:00 am the following day the clock is 10 minutes fast, it reads 10:10.

In the 4 hours 50 minutes until it reads 3:00 pm, it gains (290/1440)(10) minutes.

4 hours 50 min = 290 min and 24 hours = 1440 minutes

So the clock gained another 2.0138888.. minutes

The clock is now 12.0138 minutes ahead.

What time is the "real" time? (Or as Chicago would sing "Does anyone really know what time it is?")

Answer 2

The steps are:

 

1. Calculate how many minutes the clock gains each hour. If it gains 10 minutes in 24 hours, how much does it gain in (only) 1 hour? Hint: 1 hour is a "fraction" of 24 hours, so we need the same fraction of 10 minutes: 1/24(10) minutes

 

2. How many hours is it from the starting time the clock was set and the time we are asked to check? Hint: Since it's the next day, and later in the day, it will be more than 24 hours.

 

3. Multiply answers from #1 and #2 to get the total minutes the clock gained incorrectly. Why multiply? Because if it gains x minutes in 1 hour, it gains 10 times x minutes in 10 hours.

 

4. Calculate the true time by adjusting the end time by the amount that was incorrectly gained (from #3) . If it gained time, will it look like it is earlier or later than it really is? How can you adjust it to cancel out, or reverse the gain?

 

 

If you have trouble understanding or completing any of the steps, let us know.