AIBU to ask for help with an A-Level Maths question?

[MathsQuestionxx]

DD is doing a distance learning A-Level Maths course. She is struggling to answer the attached maths question.

Does anyone have any ideas?

Thanks in advance for any help!

My solution to part a). Very important: sketch it first, with vectors a and b in any direction.

Hopefully attaches this time:

Nope, I've made a mistake in the working. Correct solution coming!

@letsgomaths
Thank you!

Hopefully this is the right answer for part a.

Answer to b) attached.

Answer to c) is 2:3, because BQ is 2/5 of BC.

@letsgomaths
Thank you so much! DD has now understood where she had gone wrong, thanks to your advice!

Glad that helped. My general advice with vector questions is:

• always draw it, especially if no diagram is provided, as in this question;
• plan everything using the CAPITAL letters first: it makes it much easier.