Question

an AP, if a = - 5, l = 21, and S = 200, then n is equal

Answer 1

Step-by-step explanation:

solution:

According to ap series we know that:

According to A.P:

=>S=n/2[a+l]

=>200=n/2[-5+21]

=>200=n/2[16]

=>200=8n

=>n=200/8

=>25

verification:

=>S=n/2[a+l]

=>S=25/2[-5+21]

=>S=25/2[16]

=>S=25×8=200