Question

wil medel + fan
which proportion can be used to determine what number is 15% of 30?
a.15/30=x/100
b.15/100=x/30
c.15/100=30/x
d.30/100=15/x
help and explain how i do it
plz help

Answer 1

You might actually do the work to find 15% of 30, and then look backwards to determine which of the four possible answers is closest to what you've actually done.

Answer 2

i dont know how to do it

Answer 3

Find 15% of 30.
1. Convert 15% to a decimal fraction: 15/100 = 0.15
2. Multiply 30 by 0.15 (could you do this, please?)

Answer 4

yes

Answer 5

okay its 4.5

Answer 6

that's right! that 4.5 is 15% of 30.

Now, go back and review the four answer choices. Which one shows an approach closest to the one we've used here?

Answer 7

ok

Answer 8

omm b

Answer 9

Let's check out (b).

b.15/100=x/30

Substitute x=4.5. (We saw earlier that 15% of 30 is 4.5.)

Answer 10

yep

Answer 11

\[\frac{ 15 }{ 100 }=?=\frac{ 4.5 }{ 30 }\]

Answer 12

I'm asking you to determine whether or not this equation is true.

Answer 13

omm true?

Answer 14

try using cross multiplication
(15)(30) = (4.5)(100)

Answer 15

Yes, you'll need to prove mathematically whether or not the equation is true.
Please cross-multiply, as U. D. has suggested.

Answer 16

ok iso multiply 15 time 100 and 30 time 4.5 ?

Answer 17

ment 15 time 30 and 100 time 4.5

Answer 18

Actually, cross-mult in the case of \[\frac{ 15 }{ 100 }=\frac{ 4.5 }{ 30 }\]... would be appropriate. 15*30 is one such mult.; the other is 4.5*100. Determine wehther is this is true or false, please.

Answer 19

true

Answer 20

Way cool. That means that your choice of (b) was appropriate!

Answer 21

Always check your results, whenever that's possible.

Answer 22

so im wrong

Answer 23

Why would you think that? You found that (15)(30)=450 and that 4.5(100)=450.

Is 450=450?

Answer 24

yea

Answer 25

that means your answer is correct!

Answer 26

oh im tag u in my next question and thx