Percent help

[azajewel]

can anyone tell me if I am correct here:

what percent of 80 is 4? 3.2

11
---
20 as a percent is? 0.55

 

[Loren]

Second answer is correct.

To check "what percent of 80 is 4? 3.2", plug 3.2% in place of "what percent" and see if it works out. Here we go.

3.2% of 80 is 4?

.032 X 80 = 4???

.032 X 80 = 2.56 Oops. 3.2% appears to be wrong.

 

[Mrspi]

can anyone tell me if I am correct here:

what percent of 80 is 4? 3.2

11
---
20 as a percent is? 0.55

NEITHER of your answers are correct, I'm afraid.

You might want to try using this approach. You can use this proportion for MOST percent problems:

part / whole = percent / 100

For example, if you want to know "what percent of 80 is 4?" you'd set it up this way:

4 / 80 = p / 100

Now, solve the proportion. Start by "cross-multiplying":

80*p = 4*100
80p = 400
(80p)/80 = 400/80
p = 5

So, 4 is 5% of 80.

You can solve your second problem the same way.

 

[azajewel]

thank you for explaining!

 

[BigGlenntheHeavy]

\(\displaystyle \frac{4}{80} \ = \ \frac{1}{20} \ = \ .05 \ = \ 5\%\)

 

[Loren]

Yes, I screwed up. For the second answer, 0.55 is the correct value as expressed as a decimal but not as a percent.

 

[BigGlenntheHeavy]

What percent of 80 is 4?

\(\displaystyle 4 \ is \ \frac{1}{20} \ of \ 80 \ [(4)(20) \ = \ 80] \ or \ 4 \ is \ .05 \ of \ 80, \ \bigg(\frac{1}{20}\bigg) \ = \ .05,\)

\(\displaystyle hence, \ 4 \ is \ 5\% \ of \ 80. \ Check: \ (5\%)(80) \ = \ (.05)(80) \ = \ 4.\)