look at the image
let the intersection point be called X
PQX is a straight line
<RQX = 180 - <PQN - <NQR = 10 degree
same for the other side
therefore <XRQ = <RQX = 10 degree
angle sum property of triangles = add up to 180
therefore <QXR (the question) = 180 - 10 -10 =160
hope it helped