Question

30 + n ≥ 50
a. n ≥ -20
b. x ≤ 20
c. n ≥ 20
d. n ≥ 80

Answer 1

`30 + n \geqslant 50 \\ n \geqslant 50 - 30 \\ \boxed{n \geqslant 20}`

c. n ≥ 20 is the right answer.