WebMar 11, 2024 · answered In an Ap, a=1, an=20, sn=399 then find n Advertisement Answer 3 people found it helpful pragyanrana31 Answer: Sn=n/2 (a+l) . . 399=n/2 (1+20) . . 399*2/21=n . . 19*2=n . . N=38 . . Hope this helps you . . Pls mark Brainliest answer! ️ Find Math textbook solutions? Class 6 Class 5 Class 4 Class 3 Class 2 Class 1 NCERT Class 9 … WebIn an AP if a = 1, an = 20 and Sn = 399, then n is (A) 19 (B) 21 (C) 38 (D) 42 Home Get Answers to all your Questions Home NCERT In an AP if a = 1, an = 20 and Sn = 399, then n is (A) 19 (B) 21 (C) 38 (D) 42 #Arithmetic Progressions #NCERT #Maths #Exemplar Maths for Class 10 #1.3 #5.2 #5.3 #5.4 #5.1 #9.2 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
In an AP, if d = -4, n = 7, an = 4, then a is, a. 6, b. 7, c. 20, d. 28
WebIn an AP if a = 1, an = 20 and Sn = 399, then n is _____. CBSE English Medium Class 10. Question Papers 939. Textbook Solutions 33590. MCQ Online Mock Tests 12. Important … WebIn an AP if a = 1, a n = 20 and S n = 399, then n is 38. Explanation: ∵ S n = n 2 [ 2 a + ( n - 1) d] 339 = n 2 [ 2 × 1 + ( n - 1) d] 798 = 2 n + n ( n - 1) d ........ (i) And a n = 20 ⇒ a + ( n - 1) d = … csf in the body
In an AP: (i) given a = 8, an = 62. Sn = 210, find ‘n’ and ‘d’.
WebOct 25, 2015 · In an AP, if a=1,an=20 and Sn= 399, then n=? Advertisement Expert-Verified Answer 603 people found it helpful Brainly User since , an = a+ (n-1)d 20 = 1 + (n-1)d 19 = … WebFeb 22, 2013 · In an A.P. , if a = 1, an= 20 and sn =399, then n is? Share with your friends 1 Follow 0 Jai Prakash, added an answer, on 22/2/13 we know from that formula that, Sn = n/2 (a + an) 399 = n/2 (1 + 20) 399*2 = n (21) n = 798/21 = 38 Therefore n = 38 Was this answer helpful? 3 View Full Answer WebSum of n terms of AP is given by: S n = n 2 2 a 1 + n-1 d where a 1 = first term, d = common difference. S 24-4 = 24-4 2 2 × 1 + 24-4-1 13 ∵ d = 13, n = 24, a 1 = 1 S 20 = 20 2 2 + 19 × 13 = 2490. a n-4 = a 1 + n-4-1 d a 24-4 = 1 + 24-4-1 13 ∵ d = 13, n = 24, a 1 = 1 a 20 = 248. Therefore, the ordered pair S n-4, a n-4 is equal to (2490 ... csf investment returns