Answer:
Step-by-step explanation: <u>Speed</u> is distance an object travelled per unit time.
It is represented by letter v and can assume various units.
1) 

v = 18 miles per hour
Her average speed is 18 mph.
2) Rearraging formula for distance:
d = v.t
d = 70 * 4
d = 280 miles
You would travel 280 miles.
3) 

v = 52.5 mph
My average speed is 52.5 mph.
4) Rearranging formula to determine time:


t = 2.34 hours
It will take 2 hours and half to arrive in Leeds. So, we will be expected to arrive at 12:04.
5) The unit change but the way of calculating time is the same.

t = 500 s
or t = 8.34 minutes
It will take, for an athlete to run 2000m, 8.34 minutes.
6) a) All units must match, so for a speed in mph:
45 minutes is 0.75 hours. Total time is 8.75 hours.

v = 560 mph
The average speed is 560 mph.
b) 

t = 6.67 hours
Sam will take 6.67 hours to covered the distance.
It should be 4 since it is rise over run so it should be 4/1 and that equals positive 4
The half-life of the radioactive substance is 67.95 hours.
Rotate one of them so the right angle is in the same orientation as the other one.
1. AB = DE
2. CB = FE
3. AC = DF
4. Compare the length of two known sides: cb and EF
CB = 3 and EF = 8
8/3 = 2 2/3 scale factor
5. Ab is side de. Multiply the length of ab by the scale factor:
4 x 2 2/3 = 10 2/3
6. FD = sqrt ( 10 2/3^2 + 8^2)
FD = 13 1/3