Maths homework help please

The vector p has a magnitude 5 and direction due north and the vector q has magnitude 7 and direction on a bearing of 125°
A) Find the magnitude and direction of vectors p+q and p-2q
B)the vector p+kq where k is a constant has direction due east. Find the value of the constant k

Okay so I did part A and got p+q to be 5.82 and p-2q to be 17.35

I don't understand how to do part B
Any help would be appreciated
Thanks

If it's due East, the j-component (north-south component) will be 0. Write out what the vector p+kq is in terms of k and see what value of k makes the j component 0.

Wait so would it be k=-p/q
So k=-5/7
Or have I misunderstood

I don't understand what you're doing. Add the vectors p and kq together to get a new vector, which is just in terms of k. You look at the j-component of this vector and see which value of k makes the j-component 0.

I'm really sorry I'm still a little Confused I drew a right angled triangle where the vertical is P=5 and the horizontal is kq =7k
So 7k^2 +5^2 then square rooted gives the hypotenuse which is root 74k am I right so far

no. What year are you in? Do you know how to add vectors together (without drawing diagrams)?

If you want to make a right angled triangle: Your first vector is P, which is correct, it's 5 units up, but then next vector is kq, whose magnitude is 7k, but you have to make sure you get it's direction right, it's at a 125deg bearing and you have to join P and kq together "tip to tail". With the tail of kq on the tip of P. This makes kq the hypotenus. Your resultant vector (from the tail of P to the tip of kQ) should be a horizontal line (which is the other leg of the right angled triangle)