X + 19 + 7x + 9 = 180
8x + 28 = 180
8x = 180 - 28
8x = 152
X = 152 : 8
X = 19
Answer:
B
Step-by-step explanation:
I am assuming that the university has much more than 100 students so 100 people is just a small sample.
1 kilometer = 1000 meters so 12 kilometers = 12000 meters
10 laps (400 meters/lap) = 4000 meters
12000/4000 = 3
Answer: 3 days
The mass of the rock in kg is 90,000 kg
