# What is the solution to the proportion x/(12-x)=5/15?

Apr 29, 2015

Solving this would require cross multiplication

we are given
$\frac{x}{12 - x}$ $=$ $\frac{5}{15}$

on cross multiplying:
15 is taken to the L.H.S numerator and (12 - x) is taken to R.H.S numerator

we get:
15$x$ $=$ 5(12 - $x$)
15$x$ $=$ 60 - 5$x$
20$x$ $=$ 60

$x$ $=$ 3

so our proportion is:

$\frac{3}{9}$ $=$$\frac{5}{15}$

note: on solving both fractions we get equal value of 0.33 on both sides thus they are in proportion as L.H.S $=$ R.H.S