(10x + 20 y)/(x+y) = k
10x + 20y = kx + ky
10x - kx = ky - 20y
x(10-k) = y (k-20)
x/y = (k-20)/(10-k)
Insert the values for k
A) 10----k cannot be 10 since denominator will be 0. Eliminate.
B) 12----
x/y = 4/1
4y=x, this cannot be possible since y>x and both the numbers are positive. Eliminate
C) 15----
x/y=1/1, x=y, same reason as above. Eliminate.
D) 18----
x/y=1/4, 4x=y, this is the only possible answer which satisfies all the above conditions.
E) 30----
x/y = -(10/20). x, y and k are all positive numbers, Eliminate.
Hence Answer is D.
Whats the OA?
