Video Transcript
Given that a water tap leaks 7800
liters of water in five hours, find the leakage rate per minute.
So, from the question, what we know
is that 7800 liters of water leak in five hours. So then, what we wanna do, first of
all, is work out how much is going to leak per hour. And to do that, we’re gonna divide
each number by five, so divide our 7800 by five and divide our five hours by
five. And that’s because if we do that,
we’ll get one hour. So, when we do that, what we’re
gonna find out is that we get 1560 liters every hour. And that’s because if you divide
7800 by five, that’s what we get.
And what we could have used is the
bus stop method to have worked this out. Because we could have done 7800
divided by five. So, fives into seven go one
remainder two. So, then we carry that two. And we look at fives into 28, go
five remainder three. Then, what we’ll have is 30. So, we go fives into 30. This is six with no remainder. And then, finally, fives into zero
is zero, which gives us our 1560.
So, great, that’s correct. So, have we solved the problem
because we found out what the hourly leakage is because we found out that 1560
liters of water leak from the tap every hour? Well, no, because what the
question’s actually looking for is the leakage rate per minute. So, what are we gonna do to work
out what it’s going to be per minute. Well, we know that one hour is
equal to 60 minutes. So therefore, what we’re gonna do
is divide our 1560 by 60.
So, when we do this, what we’re
gonna get is 26 liters in one minute. So, we know that it’s gonna leak 26
liters in a minute. So again, in this question, we
could use a calculator if we got one. But if we want to do a written
method, I’m gonna show you how to do that, so how to divide 1560 by 60.
We might think “Well, how are we
going to do that?” We start at the bus stop method,
but it’s 60 into 1560. Well, the first thing we can do is
actually divide both bits by 10 because that would give us the same answer. So, instead of doing 1560 divided
by 60, we can do 156 divided by six. So then, if we look at the number
of sixes in one, well, it doesn’t go. And there’s a remainder of one. So then, we have sixes into 15,
which go two remainder three. And then, we do sixes into 36,
which gives us six.
So therefore, we get 26, which is
again what we got in our answer. So therefore, this would give us
our final answer. And that is that given that a tap
leaks 7800 liters of water in five hours, then the leakage rate per minute is 26
liters per minute.
