The number of common terms in the progressions 4,9,14,19,.......up to 25th term
and 3, 6, 9, 12,........, up to 37th term is:
Explanation
First A.P. 4, 9, 14, 19, ..., 48 to 25th term
Here, a=4, d=5
So, a25=4+24(5)=124
Second A.P. 3, 6, 9, 12, ..., 48 to 7th term
Here, a=3, d=3
So, a7=3+36(3)=111
As, LCM (5, 3) = 15
So, we have, 9+(x−1)≤111
⇒9+15n−15≤111
⇒15n−6≤111
⇒15n≤117
⇒n≤7.4. So, n=7
Explanation
First A.P. 4, 9, 14, 19, ..., 48 to 25th term
Here, a=4, d=5
So, a25=4+24(5)=124
Second A.P. 3, 6, 9, 12, ..., 48 to 7th term
Here, a=3, d=3
So, a7=3+36(3)=111
As, LCM (5, 3) = 15
So, we have, 9+(x−1)≤111
⇒9+15n−15≤111
⇒15n−6≤111
⇒15n≤117
⇒n≤7.4. So, n=7