If the ratio of x to y is 4 to 5, then (y-x)/(x+y)?
Choose the correct option:
A) -7/3  B) -3/7  C) 1/9  D) 1  E) 7/3
I believe this problem can be solved using algebra.   The ratio of x to y is 4 to 5 means   (x/y)=(4/5)   Cross-multiply   4x = 5y   x = (4/5)*y   Then, substitute x in the original equation in the problem with the value we just found.   (y - (4/5)*y) / ((4/5)*y + y)   = ((1/5)*y) / ((9/5)*y)   Simplify by canceling the y in the numerator with the y in the denominator.   (1/5) / (9/5)   = (1/5) * (9/7)   The 5s cancel each other out, and you are left with 1/9.
<result>C</result>
If the ratio of x to y is 4 to 5, then (y-x)/(x+y)?