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

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- May 19th 2010, 02:53 AMRubicon244Solving 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 AMProve It
If $\displaystyle x + y = 25$ then $\displaystyle y = 25 - x$.

So from the ratio

$\displaystyle x:y = 4:3$

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

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

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

$\displaystyle 3x = 100 - 4x$

$\displaystyle 7x = 100$

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

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

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

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