A particle is moving along the curve y= 5*sqrt{4 x + 4}. As the particle passes through the point (3, 20) its x-coordinate increases at a rate of 4 units per second. Find the rate of change of the distance from the particle to the origin at this instant.

I solved this problem and my answer yielded me: 10

However the computer isn't accepting this I must have done something wrong...

Thanks!