Question

in an AP the first term is 13 and fourth term is 7.if the last term is -1,what is the number of terms?please someone answer this tomorrow is my exam

Answer 1

8

Step-by-step explanation:

a = 13 , 4th term = a + (4-1)d =a+ 3d = 7

=> d = (7 -13)/3 = - 2

last term = - 1

a+ (n-1) d = - 1

13 + (n-1) ×(-2) = - 1 => n = 8