ANSWER:
50% increase
The percent of change of 30 increased to 45 is a 50% increase.
STEP-BY-STEP EXPLANATION:
% of change = [ ( New amount - original amount ) / original amount ] × 100%
Let % of change = x
x = [ ( 45 - 30 ) / 30 ] × 100%
x = ( 15 / 30 ) × 100%
x = ( 1 / 2 ) × 100%
x = 0.5 × 100%
x = 50%