If Q varies inversely as the square root of R and Q=2 when R=4, what is Q when R is 25?

does Q=625
im not sure can someone double check it for me.

Q = k/sqrt(R) = 2,

k / sqrt(4) = 2,
k = 2*sqrt4 = 2*2 = 4.

Q = k/sqrt(R) = 4/sqrt25 = 4/5.