(i) 60 – x ≥ 0 ⇒ x ≤ 60
(ii) 50 – y ≥0 ⇒ y ≤ 50
(iii) 100 – (x + y) ≥ 0 ⇒ x + y ≤ 100
(iv) x + y – 60 ≥ 0 ⇒ x + y ≥ 60
ABCD is the solution region
A(10, 50) Z = Rs 510
B(50, 50) Z = Rs 610
C (60, 40) Z = Rs 620
D (60, 0) Z = Rs 560
Cost is minimised to Rs 510 at A (10,50)