Express $2.00 as a percentage of $8.00 ?

2 Answers
Mar 9, 2018

25%

Explanation:

First let's think about a normal percentage as a ratio.

If I wanted to think about #4%# as a ratio I would say well... That's 4 parts of #100%# or #4/100# and from there I could simplify the fraction into #1/25# and now I have a mathematical representation of #4%#. Anything that I multiply by #1/25# will give me #4%# of that thing.

"How does this help me?" you say
I'm very glad you asked

Let's think about #8# as our #100%# and we want to find 2 parts of 8, so using what we just learned we say that "2 parts of 8 is the same as #2/8#." To turn #2/8# into a percentage we just need the denominator to equal 100 since earlier we said that 8 is our #100%#

We could use an equation for this, so let's use an equation for this :D

We know that #8*("some number") = 100# so;
#8x = 100#

#1/8*8x = 100*1/8 = 100/8 = 25/2 = 12.5#

Now we know that if we multiply the denominator by 12.5 we will get 100 and if we multiply the numerator by 12.5 we will get a ratio with 100 as the denominator, so our percentage must be the numerator!

#2/8*12.5/12.5 = 25/100 = 25%#

Mar 9, 2018

#25%#

Explanation:

Given: #($2)/($8)#

We have:

#(color(red)cancelcolor(black)$2)/(color(red)cancelcolor(black)$8)=1/4#

Now, we convert #1/4# to a percent.

We got:

#1/4*100%=25%#

#:.($2)/($8)=25%#