Question

How many terms are there in the ap 20, 25, 30, ......, 130?

Answer 1

Answer: n=21

Step-by-step explanation:

d=5      a= 20

last term = a+(n-1)d

          130=20+(n-1)5

130-20=5n-5

110-5=5n

105=5n

n=105/5

n=21