Question

The first, second and last terms of an A.P. are respectively 4, 7 and 31. How many
terms are there in the A.P.

Answer 1

Answer:

an=a+(n-1)d

31=4+(n-1)3

27=3n-3

30=3n

n=1

Answer 2

Step-by-step explanation:

Given : a1=4 , a2=7 and an=31

d= a2-a1=7-4=3

we know that : an= a1 + (n-1)d

31 = 4+(n-1)(3)

31=4+3n-3

31-7=3n

24=3n

24/3=n

n=8 Answer

Hope this will help you!