Question

the number of terms of an AP 5,9,13,...,185 is
a 45
b 41
c 50
d 46
pls help me answer this​

Answer 1

Answer:

45 is the correct answer

Answer 2

Step-by-step explanation:

a=5

d=9-5=4

tn=a+(n-1)d

case 1)

45=5+(n-1)4

40=(n-1)4

n=11

thus 45 is 11 term of AP

Case 2)

41=5+(n-1)4

36=(n-1)4

n=10

41 is 10th term of AP

Case 3)

50=5+(n-1)4

45=(n-1)4

since value of n is not a integer

50 is not a term of AP

Case 4)

t11=45

thus, t12=t11+4=49

thus 46 is not a term of AP