Step-by-step explanation:
2 × 10⁸ - 7 × 10⁷
= 200,000,000 - 70,000,000
=130,000,000
= 1.3 × 10⁸
Answer: 
Step-by-step explanation:
The distances must be expressed in the same uni.
Let's express the distance in meters.
We know that Dory lives 2.5 miles from school.
Since:

The distance in kilometers is:

Since 
The distance in meters is:

Jim lives 3.2 kilometers from school. The distance in meters is:

Chris lives 3,000 yards from school.
Since:

The distance in meters is:

Therefore, the order of the students from closest to farthest from school is:

Car: distancec = 105 km + (90 km/hr)(3 hrs)
Cycle: distancem = ratem(3 hrs)
Equate these 2 distances: 105 km + 270 km = ratem(3 hrs)
Then 375 km / 3 hrs = ratem = 125 km/hr (average speed of the motorcyclist)
Answer:
21) B. (5,45)
22) B. As the temperature decreases, hot chocolate sales increase.