Question

x% of y is z and (x + 10)% of y is equal to 2z, then y when expressed in terms of z is

Answer 1

xy/10=z,(x+10)y/100=2z

Answer 2

y=zx/100,yx+10y=200z

Answer 3

zx/100+10zx/100=200z

Answer 4

100z+10y^2-200zy

Answer 5

so we have:
\[z = \frac{xy}{100} \rightarrow y = \frac{100z}{x}\]
\[2z = \frac{y(x+10)}{100} = \frac{2xy}{100}\]
From 2nd equation you can find that x=10
thus
\[y = \frac{100z}{10} = 10z\]

Answer 6

2xy/100 how?

Answer 7

yx+10y/100

Answer 8

i substituted previous value for "z" and multiplied by 2

Answer 9

A one line Mathematica solution is attached.

Answer 10

oh ok

Answer 11

ahh sorry i realized i didn't make that clear

\[2z = 2(\frac{xy}{100}) = \frac{y(x+10)}{100}\]

Answer 12

k no problem

Answer 13

thanks @robtobey