Answer:
52.94%
270 minutes
Step-by-step explanation:
1. 9 plants - 15 minutes
x plants - 75 minutes
Cross multiply
15x = 75 x 9
15x = 675
Divide both sides by 15
x = 675/15
x = 45 plants
45/85 x 100
= 52.94%
2. 90% of 180
= 90/100 x 180
= 162 plants
9 plants - 15 minutes
162 plants - x minutes
Cross multiply
9x = 162 x 15
9x = 2430
Divide both sides by 9
x = 2430/9
x = 270 minutes or 4 hours 30 minutes.