Look at the answers and be logical, try rounding up so instead of 45% try 50% now 22.5 would be half the number, have a look at the answers and see what is closest to double 22.5. C looks reasonable. Hope I helped, have a nice day :)
Answer:
Her centripetal acceleration during the turn at each end of the track is 
Step-by-step explanation:
Total distance covered in one round , D= 400 m
Time taken to cover one round , T = 1 min 40 s = 100 sec
Speed of runner , 
Now centripetal acceleration is given by

where 


Thus her centripetal acceleration during the turn at each end of the track is 
Answer:

Step-by-step explanation:

To get
you needed to divide the numerator and denominator by 3.
Answer:
5n
Step-by-step explanation:
Summarizing what we know:
Casey has n nickels, and Meghan 4 times as many: 4n
Then the total number of nickets these two people have is n + 4n, or 5n.