00:02
All right.
00:03
Identify whether the following problems are looking for a percentage, rate, or base, then solve for the unknown.
00:09
So when you set up a problem like number one where it says 85 % of 78 is what amount, there's three things we have to know here.
00:25
The first one is we have to know that 85 % has to be written as a decimal.
00:30
So you always take that two places to the left.
00:33
So that makes that .85.
00:36
The word of, of means times.
00:42
So that's huge.
00:43
Every time you see the word of, you're thinking a time sign.
00:46
So .85 times 78.
00:50
Well now it says is, well that means equals.
00:54
So is means equals and what amount? well that's your unknown.
00:58
So there's your variable, right? so literally on your calculator you're going to do .85 times 78 and get 66 .3.
01:08
Question number two says 45 % of 70.
01:12
So 45 % has to be rewritten as a decimal.
01:15
So i move that two places to the left.
01:17
Of 70, so times 70 is what number? so it equals x.
01:23
And punch that in on a calculator, .45 times 70 gives you 31 .5.
01:31
Problem three says, oh, so i guess earlier i was asking is this a percent, percentage rate or base? so what we're looking for here is what amount? so that's just a regular base.
01:45
It's not a percent or anything.
01:47
It's, they gave you a percent in the problem so you're not finding a percent.
01:51
All right, let's look at three.
01:53
It says seven is, so it changes the wording up in the order of the wording a little bit.
01:58
But we know is means equals.
02:00
So seven is 35%.
02:03
So again, that decimal has to be .35 of what number? so we're looking for another number.
02:09
This time in order to solve for x, i'll divide by .35.
02:13
Seven divided by .35 is 20.
02:18
Question number four.
02:20
Let's see, scroll here a little bit.
02:23
Question number four says 110%.
02:27
So i'll write it out.
02:29
Of what number, so times what number is, that's equals 660.
02:35
Now the reason i wrote this out is even though this is a percent, i still have to go two decimal places to the left.
02:42
This percent just happens to be more than one and that's okay.
02:46
Oh, i don't need the percent sign anymore.
02:48
So that would be 1 .1 times x equals 660.
02:55
So in order to solve for x, i'll have to divide by 1 .1 or 1 .10.
03:01
It doesn't matter.
03:02
X is going to be 600.
03:07
Question five reads 120 is 180%.
03:14
So there's your 180.
03:16
I got to move two decimal places to the left to make it a decimal.
03:20
Of what number? so times x.
03:22
So 120 divided by 1 .8 or 120 divided by 1 .80.
03:28
That's 66 .6 repeating, so 66 and two thirds...