For this case, you must use the given expression, taking into account that:
n = number of days.
We have then that for day 21, n = 21.
Substituting we have:
a21 = 100 + (21-1) * 4
a21 = 180
Answer:
she sprints 180 yards on day 21

Solution:
1) m is atleast 25
"at least" means greater then or equal to
Therefore,

2) p is less than 48

3) h is atmost 56
"at most" means less than or equal to

4) k is no greater than 9
Which means k is less than or equal to 9

5) w is no less than 0
Which means, w is greater than or equal to 0

Answer:
C
Step-by-step explanation:
Good Luck and I hope you do well :)
D is correct because 150+50=200 and if 200sf is 4 hours and 150 is 2 1/2 hours 1/2+1/2=1