Published by:
CGP EDU Academic Team
Published on: August 13, 2026
The sum of the first 20 terms common between the series 3 + 7 + 11 + 15+ ..... and 1 + 6 + 11 + 16+ ...... is
Text Solution
Verified by ExpertsThe correct answer is:
D
4020
S 1 
3, 7, 11, 15, ....... 
c.d = 4 
d 1 =4;
S 2 
1, 6, 11, 16,.. .. 
c .d = 5 
d 2 = 5
Every 5 th term of S 1 and 4 th term of S 2 will be same
Terms common to both AP will have a = 11 and d = 20
Hence, 
[(2 x 11) + (20 - 1) 20]
= 10x402
= 4020
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems
Let the sum , written in the rational form be (where p and q are co-prime), then the value of is…
Let and be two numbers where < . The geometric mean of these numbers exceeds the smaller number…
Let a 1 , a 2 , a 3 ,..........., a 11 be real numbers satisfying a 1 = 15, 27 - 2a 2 > 0 and a k =…
If , where a, b, c N and a, b, c [1, 15], then a + b + c is equal to
If then the value of is
If the roots of the equation 10x 3 -cx 2 -54x - 27 = 0 are in harmonic progression, then the value …