Answer:
The velocity is 8.93 meters/second.
Step-by-step explanation:
It is given that Elena runs for 28 seconds and finishes at 250 meters.
Here the displacement is 250 meters and the time is 28 seconds.
We know that 
Substitute displacement = 250 and time = 28 in above formula.

meters/second
Hence, the velocity is 8.93 meters/second.
Square root 2,025 to get 45.
Or, multiply 45 × 45 to get 2,025.
Answer: 45
Should be 59.490 just because if you have to round the tenth and the hundredth together
Consider, please, this solution/explanation:
1. suppose, that number of cars is 'x', numbers of buses is 'y'.
2. according to the condition 'a total of 32', it means that x+y=32. This is the 1st equation.
3. according to the condition in one car are 3x persons, in one bus are 27y persons, and totaly 3x+27y=408 people. This is the 2d equation.
4. if to solve the system of two equations:

Answer: 13 - b., 19 - c.