This question is based on load factors and speed with the question
asking you to determine the change in speed.
Note: The aircraft is in steady level flight so the original load factor
will be 1g
Furthermore Lift is proportional V^2 and lift is also proportional to
load factor
It follows that Load factor is proportional to V^2
New LF / Original Load Factor = (new speed / original speed)^2
New speed = 300 x SQRT (1.2 / 1) = 329 kt
The speed therefore increases by 30 kt