Answer:
x = 120
Step-by-step explanation:
Express the ratios as equivalent fractions, that is
[tex]\frac{x-20}{x+280}[/tex] = [tex]\frac{1}{4}[/tex] ( cross- multiply )
4(x - 20) = x + 280
4x - 80 = x + 280 ( subtract x from both sides )
3x - 80 = 280 ( add 80 to both sides )
3x = 360 ( divide both sides by 3 )
x = 120
