Question

what is the comman difference of an A.P. in which option 15,12,19,21​

Answer 1

Answer:

3 common difference

Step-by-step explanation:

3 common difference

Answer 2

Answer:

Here first term a=5 and common difference 

d=12−5=7

Suppose nth term of the A.P. is 145

Now, Tn=a+(n−1)d

∴145=5(n−1)(7)

∴145−5=7(n−1)

∴140=7(n−1)

∴20=n−1∴n=21