Question

3.

(i) Is 68 a term of the A.P. 7,10,13,...?
(ii) Is 302 a term of the A.P. 3,8,13,...?
(iii) Is -150 a term of the A.P. 11,8,5,2?

Answer 1

1-
Use formula of nth term=a+(n-1) d
68=7+(n-1) 3
61/3+1=n
Here n is fractional but n can't be fractional. So 68 is not a term of above series
2-
a=3
d=8-3=5
$A_n=302An=a+(n-1)d$
302=3+(n-1)5
302-3=(n-1)5
299=5n-5
299+5=5n
304=5n
n=304/5
So it is not a term of the A.P. because n is in the fraction form.

3-
Use formula of nth term=a+(n-1) d
-150=11+(n-1) 3
-161/3+1=n
So it is not a term of the A.P. because n is in the fraction form.