Question

Marika is training for a track race She starts by sprinting 100 yards . She gradually increases her distance , adding 4 yards a day for 21 days how far does she sprint on day 21 

using an=100+(n-1)4

Answer 1

180 yards on day 21

Explanation:

just took on A P E X !!

Answer 2

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