2006-09-24 18:09:54 · 12 answers · asked by Tina 1 in Science & Mathematics ➔ Mathematics
6.75
2006-09-24 18:17:22 · answer #1 · answered by cynthetiq 6 · 2⤊ 1⤋
There are two ways to do this ...
First .. 30% = .30 as a decimal. Since "of" in mathematics means multiply ... you take .30 times 22.50. That makes 6.75.
Or you can set up a proportion
30 over 100 = ?? over 22.50
30/100 = x/22.50
Then you have to use the rule of cross multiplication.
30 times 22.50 = 100 times x
so 100x = 22.50(30)
100x = 675
divide both sides by 100
so x = 6.75
2006-09-24 18:57:21 · answer #2 · answered by TripleFull 3 · 2⤊ 0⤋
30% is the same thing as 30 upon 100..and "of" means multiply.so,u simply put 30 upon 100 multiplied by 22.50,which gives you 6.75
2006-09-25 00:48:20 · answer #3 · answered by sweetfloss8 2 · 1⤊ 0⤋
Easiest way to figure out in your head:
30% of 10 = 3 *2 = 6 (cause the 20)
And since you already know 30% of 20 is 6 then 30% of 2 is .6
so you 6 + .6 = 6.6
Now you have .5 and you know 30% of 1 is .3 so half that (.5) is .15
Now you have 6 + .6 + .15 = 6.75
All that is easily done in your head.
Whenever you want to find percentages, take them from bigger numbers first (like 10, 100, they are the easiest) and simplify from there. Or you can just multiply them:
30% of 22.5 = 6.75
3 * 22.5 = 67.5 then move over one decimal and 6.75
2006-09-24 19:10:06 · answer #4 · answered by chernz 3 · 1⤊ 0⤋
30% of X = .30 * X
ergo
30% of 22.50 = .3 * 22.5 = 6.75
2006-09-25 04:59:38 · answer #5 · answered by michaell 6 · 1⤊ 0⤋
30% = .3
.3 * 22.50 = 6.75
Answer = 6.75
2006-09-24 19:05:09 · answer #6 · answered by A Lo 1 · 1⤊ 0⤋
6.75
2006-09-24 18:29:44 · answer #7 · answered by corrona 3 · 1⤊ 1⤋
6.75
2006-09-24 22:40:25 · answer #8 · answered by an0nymu$ 1 · 0⤊ 2⤋
6.75
2006-09-24 21:57:23 · answer #9 · answered by sandra 1 · 0⤊ 2⤋
6.75
2006-09-24 18:20:11 · answer #10 · answered by Confused 4 · 0⤊ 2⤋