(a) Let B represent those with degree.
Let D represent those with diploma.
Let x represent those who have both degree and diploma.

(17 - x) + x + (15 - x) + 4 = 30
36 - x = 30
x = 36 - 30 = 6.
(b)
\(< PNM = 75°\) (corresponding angle)
\(\therefore NQR = 125° - 75° \)
= \(50°\)
\(< NPM = \frac{180° - 125°}{2}\)
= \(\frac{55°}{2}\)
= \(27.5°\). (Base angles of an isosceles triangle).