Ques. 1JEE Main 2024, 27 January (Morning Shift)
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 :
- 9
- 8
- 5
- 7
Answer
(4) 7
Solution
Last terms: T25=4+24 5=124, T37=3+36 3=111
∵ common terms form an A.P. with d=LCM(5, 3)=15, first common term =9
⇒ common terms: 9, 24, 39, up to 111 (the smaller last term)
9+15(m-1) 111 ⇒ m-1 6.8 ⇒ m=7
(terms 9, 24, 39, 54, 69, 84, 99)
Answer: (4)