# Math Help - percentage % of a number

1. ## percentage % of a number

okay i'm currently studying for a ASVAB test for the military. and they have questions like the one below,

" what number is 5% of 2000 "

how would i solve for something like that?

or they have

" 35% of what number is 70 "

" if 45 is 120% of a number, what is 80% of the same number? "

" if 6 is 24% of a number, what is 40% of the same number? "

" 25% of $900= " questions like those, please help 2. Originally Posted by lambofgod " what number is 5% of 2000 " how would i solve for something like that? ...questions like those, please help To learn how to set up and solve this sort of exercise, try this lesson on "percent of" word problems. For instance, the above exercise would be set up as "(some number) is (five percent) of (2000)", or x = (0.05)(2000). 3. ok. The trick to percent problems is to move the decimal in the percent two places to the left. Example: 5% becomes 0.05 then if they question says: find 5% of 2000, you would move the decimal two places to the left, and multiply it by 2000. That is your answer. In this case 5% of 2000 is 100. so: (0.05)(2000)= 100 4. Originally Posted by lambofgod okay i'm currently studying for a ASVAB test for the military. and they have questions like the one below, " what number is 5% of 2000 " how would i solve for something like that? or they have " 35% of what number is 70 " " if 45 is 120% of a number, what is 80% of the same number? " " if 6 is 24% of a number, what is 40% of the same number? " " 25% of$900= "

try these formulas:

B=base(original number)
R=rate
P=percentage

if you are looking for the base:

$B=\frac{P}{R}$

ex.
35% of what number is 70

$B=\frac{P}{R}$

$B=\frac{70}{.35}$

$B=200$

percentage

$P=RB$

" what number is 5% of 2000 "

$P=.05(2000)$

$P=100$

rate

$R=\frac{P}{B}$

what % of 2000 is 100

$R=\frac{P}{B}$

$R=\frac{100}{2000}$

$R=5\%$