The correct option is B 3:10
Let →r be a point on a plane →r.(→i−2→j+3→k)=17 which divides line joining the points −2→i+4→j+7→k & 3→i−5→j+8→k in the ratio n:m
Therefore, →r=→r=m(−2→i+4→j+7→k)+n(3→i−5→j+8→k)m+n=(−2m+3n)i+(4m−5n)j+(7m+8n)km+n
Substituting →r in equation of plane, we get
((−2m+3n)→i+(4m−5n)→j+(7m+8n)→km+n).(→i−2→j+3→k)=17
⇒−2m+3n−8m+10n+21m+24n=17m+17n
⇒−6m+20n=0
⇒n:m=3:10
Ans: B