Video Transcript
Which of the following digital
clocks displays the time half past 4?
To help us answer this question,
we’re shown three digital clocks to choose from. These are clocks that show the time
of the day using digits. In a digital time, we have one or
two digits that represent the number of hours, followed by two dots, and then two
digits after the dots that tell us the number of minutes that have gone by. Now, the time we’re looking for
here is half past 4. Which of our three digital clocks
shows the time half past 4?
We know that for the minute hand on
a clock to make a whole turn all the way around, takes 60 minutes. One whole hour is worth 60
minutes. Now, if the minute hand is only
turned half the way around the clock, half an hour has gone by. It’s a half-past time. And because half of 60 is 30, we
know that half of an hour is the same as 30 minutes. So, if we are looking for a digital
time that shows a half-past time, the minutes part of our digital clocks should show
a three and a zero, the number 30.
But wait a moment, if we look at
our three digital clocks, we can see that they all show the number 30. They’re all showing half-past
times. We’ve got 3:30, 4:30, and 5:30. We’re going to need to think
carefully about the number that we want in the hour place. We need to find the time half past
four. And so, we’re looking for a digital
clock where there’s a four in the hours place.
There are 30 minutes in half an
hour. And so, we know at a half-past
time, the number of minutes that are shown on a digital clock is going to be 30. The digital clock that shows the
time half past 4 is the one that shows 4:30.
