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In this example we're gonna solve percent equations
of the type: unknown percent
of A is B, and we're going to set up percent equations using their replacements for certain
words
percent, multiplication, is etc. So let's see how that works with these
problems.
What percent of 140 is
3.8, well it's going to be very small, because 3.8 out of 140 is going to
be a very small number.
So let's see how to set that up. 'What' I can replace by
X, and I just need to remember that my final result is going to be a percent,
times 140, so 'of' is
replaced by times, 140 is my number
equals 3.8. In order to
get X by itself, I'm going to divide both sides by 140
and that leaves me with X on the left
on the right hand side I have 3.8 divided by
140 which is .027
and I need to remember because I'm looking for the percent
to write that as a percent. So I'm going to multiply by 100
and include my percent that would be 2.7%
Let's check. So I'm going to check
by taking .027
times 140
and that should equal 3.8
and in fact it does, so there is our
check. Part B what percent of 620
is 136.4. So X times
620 equals
136.4, divide both sides by 620, so I'm going to eliminate the step where I write
that on the left, I'm just gonna show
136.4 divided by
620 and
that's gonna give me .22
which as a percent is 22%
I'm gonna do a check. So I'm going to take .22 or 22%
of 620 and that should equal 136.4 and if you perform that computation on your
calculator you will get,
indeed get 136.4
Part C: what percent, so
X of 25, so X times 25 equals
0.05
and again I'm going to skip the step where I divide both sides by 25, I'm going to show
that computation on the right hand side
.05 divided by 25 equals
.002 which
as a percent is .2%
and I'm going to do a check
I'm going to take
.002 times 25, and that should equal
.05 and in fact it does. So the last one: 240
is what percent of 100, this one's going to end up being a little bit obvious when
you see it, so 240 equals
X times 100, if I divide both sides by 100
I get 240 over 100
equals X, so 2.4
equals X, if I write that as a percent that's 240%
so well that kind of makes sense, because it's: 240 is what percent of 100, well its
240% so let's do our check just
for grins here. So we're gonna take 2.4
which was our result times 100 and we should get 240
which indeed, we do.