6+w/15=w/200 * 50w/250=w^2/1000.
Multiply through by 3000: 18000+200w=3w^2; 3w^2-200w-18000=0.
w^2-200w/3-6000=0; w^2-200w/3+10000/9-10000/9-6000=0 (completing the square);
(w-100/3)^2=6000+10000/9=(54000+10000)/9=64000/9;
w-100/3=+sqrt(64000)/3=+80sqrt(10)/3; w=100/3+80sqrt(10)/3=117.66 or -50.994.