Question

If `bara, barb, barc` are position vectors of the points A, B, C respectively such that `3bara+ 5barb-8barc = 0`, find the ratio in which A divides BC.

Answer 1

Given : `3bara+ 5barb-8barc = 0` 

`3bara=8barc- 5barb `

`bara=(8barc- 5barb)/3 ` 

`bara=(8barc- 5barb)/(8-5) `                                 `[∵3=8-5]`

`A(bara)` divides BC externally in the ratio 8 : 5.