Question

प्र.20. A.P.: 21,18,15....... का कौन सा पद -81 he​

Answer 1

Answer:

19th term of given A.P is 81

Step-by-step explanation:

a=21

d=18-21=-3

an=81

an=a + (n-1)d

81=21+ (n-1)-3

81=21+ 3-3n

81-24=-3n

57=3n

n=57/3

n=19