question_answer

Two vectors a and b, add up to Vector c. When vector a is made 3 times as long and vector b is doubled in length, without changing their directions, then it is found that vector c is also doubled in length, without change in direction. Then which of the following is true?

A)  All three vectors must be parallel

B)  b and c must be parallel to each other, but a need not be parallel to b and c

C)  a and b must be perpendicular to each other

D)  It is impossible for three non-zero vectors a, b and c to have the property stated above