Answer:
23.225%
Explanation:
Runtime in June (x1) = 7:45 = (7 * 60) + 45 = 465
Runtime in September (x2) = 5:57 = (5*60)+57 = 357
Percentage change in Runtime :
[|x2 - x1|÷ x1] * 100%
[|357 - 465| ÷ 357] * 100%
108 / 465 * 100%
0.23225 * 100%
= 23.225%