Question:

Let \(a_n=46+8n\) and \(b_n=98+4n\) be two sequences for natural numbers \(n ≤ 100\) . Then, the sum of all terms common to both the sequences is

Updated On: Aug 17, 2024
  • 14900
  • 15000
  • 14798
  • 14602
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

The first series goes as follows: \( 46, 54, 62, 70, 78, 86, 94, 102,.... \)
The second series follows this format: Numbers \(98, 102, 106, 110,..\)
The difference between them will be hcf(4,8) = 8, which is the first common term (term of the common terms). 
The necessary order is \(102,110,118\), (the final term must be less than 468, which is the second series' hundredth term). 
\([102 + (n-1)(8) ≤ 498]\)
 If n is equal to or less than 50.5, then n = 50. 

Applying the A.P. formula summation, we get: Required sum = \(\frac{n}{2}(2a + (n - 1)d) = \frac{50}{2}(2 \times 102 + 49 \times 8) = 14900\)
The correct option is (A): 14900.
Was this answer helpful?
1
1

Questions Asked in CAT exam

View More Questions