# Solving for x and y based on ratio

• May 19th 2010, 02:53 AM
Rubicon244
Solving for x and y based on ratio
Hi,

x + y = 25

solve for x and y where ratio of x:y is 4:3

Could someone please run me through the steps for solving 2 unknowns based on a ratio?

Many thanks

Dave
• May 19th 2010, 03:07 AM
Prove It
Quote:

Originally Posted by Rubicon244
Hi,

x + y = 25

solve for x and y where ratio of x:y is 4:3

Could someone please run me through the steps for solving 2 unknowns based on a ratio?

Many thanks

Dave

If $x + y = 25$ then $y = 25 - x$.

So from the ratio

$x:y = 4:3$

$\frac{y}{x} = \frac{3}{4}$

$y = \frac{3x}{4}$.

Therefore $\frac{3x}{4} = 25 - x$

$3x = 100 - 4x$

$7x = 100$

$x = \frac{100}{7}$.

Which means $y = 25 - \frac{100}{7}$

$= \frac{175}{7} - \frac{100}{7}$

$= \frac{75}{7}$.